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NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Ex 3.3

March 6, 2026

Get Free NCERT Solutions for Class 10 Maths Chapter 3 Ex 3.3 PDF. Pair of Linear Equations in Two Variables Class 10 Maths NCERT Solutions are extremely helpful while doing your homework. Exercise 3.3 Class 10 Maths NCERT Solutions were prepared by Experienced LearnCBSE.in Teachers. Detailed answers of all the questions in Chapter 3 Maths Class 10 Pair of Linear Equations in Two Variables Exercise 3.3 provided in NCERT TextBook.

Topics and Sub Topics in Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables:

Section Name	Topic Name
3	Pair of Linear Equations in Two Variables
3.1	Introduction
3.2	Pair Of Linear Equations In Two Variables
3.3	Graphical Method Of Solution Of A Pair Of Linear Equations
3.4	Algebraic Methods Of Solving A Pair Of Linear Equations
3.4.1	Substitution Method
3.4.2	Elimination Method
3.4.3	Cross-Multiplication Method
3.5	Equations Reducible To A Pair Of Linear Equations In Two Variables
3.6	Summary

You can also download the free PDF of Ex 3.3 Class 10 Pair of Linear Equations in Two Variables NCERT Solutions or save the solution images and take the print out to keep it handy for your exam preparation.

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Maths
Chapter	Chapter 3
Chapter Name	Pair of Linear Equations in Two Variables
Exercise	Ex 3.3
Number of Questions Solved	3
Category	NCERT Solutions

NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Ex 3.3

NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Ex 3.3 are part of NCERT Solutions for Class 10 Maths. Here we have given NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Exercise 3.3

Ex 3.3 Class 10 Maths Question 1.
Solve the following pairs of linear equations by the substitution method:

Solution:

Worksheets for Class 10 Maths

Ex 3.3 Class 10 Maths Question 2.
Solve 2x + 3y = 11 and 2x – 4y = -24 and hence find the value of’m’ for which y = mx +3.
Solution:

Worksheets for Class 10 Maths

Ex 3.3 Class 10 Maths Question 3.
Form the pair of linear equations for the following problems and find their solution by substitution method:
(i) The difference between two numbers is 26 and one number is three times the other. Find them.
(ii) The larger of two supplementary angles exceeds the smaller by 18 degrees. Find them.
(iii) The coach of a cricket team buys 7 bats and 6 balls for ₹3800. Later, she buys 3 bats and 5 balls for ₹1750. Find the cost of each bat and each ball.
(iv) The taxi charges in a city consist of a fixed charge together with the charge for the distance covered. For a distance of 10 km, the charge paid is ₹105 and for a journey of 15 km, the charge paid is ₹155. What are the fixed charges and the charges per km? How much does a person have to pay for travelling a distance of 25 km?
(v) A fraction becomes \(\frac { 9 }{ 11 }\), if 2 is added to both the numerator and the denominator. If 3 is added to both the numerator and the denominator, it becomes \(\frac { 5 }{ 6 }\). Find the fraction.
(vi) Five years hence, the age of Jacob will be three times that of his son. Five year ago, Jacob’s age was seven times that of his son. What are their present ages?
Solution:

NCERT Solutions for Class 10 Maths Chapter 3 Pairs of Linear Equations in Two Variables (Hindi Medium) Ex 3.1

NCERT Solutions for Class 10 Maths

We hope the NCERT Solutions for Class 10 Maths Chapter Pair of Linear Equations in Two Variables Ex 3.3, help you. If you have any query regarding NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Exercise 3.3, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Ex 3.2

March 6, 2026

Get Free NCERT Solutions for Class 10 Maths Chapter 3 Ex 3.2 PDF. Pair of Linear Equations in Two Variables Class 10 Maths NCERT Solutions are extremely helpful while doing your homework. Exercise 3.2 Class 10 Maths NCERT Solutions were prepared by Experienced LearnCBSE.in Teachers. Detailed answers of all the questions in Chapter 3 Maths Class 10 Pair of Linear Equations in Two Variables Exercise 3.2 provided in NCERT TextBook.

Topics and Sub Topics in Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables:

Section Name	Topic Name
3	Pair of Linear Equations in Two Variables
3.1	Introduction
3.2	Pair Of Linear Equations In Two Variables
3.3	Graphical Method Of Solution Of A Pair Of Linear Equations
3.4	Algebraic Methods Of Solving A Pair Of Linear Equations
3.4.1	Substitution Method
3.4.2	Elimination Method
3.4.3	Cross-Multiplication Method
3.5	Equations Reducible To A Pair Of Linear Equations In Two Variables
3.6	Summary

You can also download the free PDF of Ex 3.2 Class 10 Pair of Linear Equations in Two Variables NCERT Solutions or save the solution images and take the print out to keep it handy for your exam preparation.

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Maths
Chapter	Chapter 3
Chapter Name	Pair of Linear Equations in Two Variables
Exercise	Ex 3.2
Number of Questions Solved	7
Category	NCERT Solutions

NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Ex 3.2

NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Ex 3.2 are part of NCERT Solutions for Class 10 Maths. Here we have given NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Exercise 3.2

Ex 3.2 Class 10 Maths Question 1.
Form the pair of linear equations of the following problems and find their solutions graphically:
(i) 10 students of class X took part in a Mathematics quiz. If the number of girls is 4 more than the number of boys, find the number of boys and girls who took part in the quiz.
(ii) 5 pencils and 7 pens together cost ₹50, whereas 7 pencils and 5 pens together cost ₹46. Find the cost of one pencil and that of one pen.
Solution:

Worksheets for Class 10 Maths

Ex 3.2 Class 10 Maths Question 2.
On comparing the ratios \(\frac { { a }_{ 1 } }{ { a }_{ 2 } }\), \(\frac { { b }_{ 1 } }{ { b }_{ 2 } }\)
and \(\frac { { c }_{ 1 } }{ { c }_{ 2 } }\) , find out whether the lines representing the following pairs of linear equations intersect at a point, are parallel or coincident:
(i) 5x – 4y + 8 = 0, 7x + 6y – 9 = 0
(ii) 9x + 3y + 12 = 0, 18x + 6y + 24 = 0
(iii) 6x – 3y + 10 = 0, 2x -y + 9 = 0
Solution:

Ex 3.2 Class 10 Maths Question 3.
On comparing the ratios \(\frac { { a }_{ 1 } }{ { a }_{ 2 } }\), \(\frac { { b }_{ 1 } }{ { b }_{ 2 } }\)
and \(\frac { { c }_{ 1 } }{ { c }_{ 2 } }\), find out whether the following pairs of linear equations are consistent, or inconsistent:
~
Solution:

Ex 3.2 Class 10 Maths Question 4.
Which of the following pairs of linear equations are consistent/inconsistent? If consistent, obtain the solution graphically.
(i) x + y = 5, 2x + 2y = 10
(ii) x-y – 8, 3x – 3y = 16
(iii) 2x + y – 6 = 0, 4x – 2y – 4 = 0
(iv) 2x – 2y – 2 = 0, 4x – 4y – 5 = 0
Solution:

Ex 3.2 Class 10 Maths Question 5.
Half the perimeter of a rectangular garden, whose length is 4 m more than its width is 36 m. Find the dimensions of the garden graphically.
Solution:

Ex 3.2 Class 10 Maths Question 6.
Given the linear equation 2x + 3y – 8 = 0, write another linear equation in two variables such that the geometrical representation of the pair so formed is:
(i) intersecting lines
(ii) parallel lines
(iii) coincident lines
Solution:

Ex 3.2 Class 10 Maths Question 7.
Draw the, graphs of the equations x – y + 1 = 0 and 3x + 2y – 12 = 0. Determine the coordinates of the vertices of the triangle formed by these lines and the x-axis, and shade the triangular region.
Solution:

NCERT Solutions for Class 10 Maths Chapter 3 Pairs of Linear Equations in Two Variables (Hindi Medium) Ex 3.2

NCERT Solutions for Class 10 Maths

We hope the NCERT Solutions for Class 10 Maths Chapter Pair of Linear Equations in Two Variables Ex 3.2, help you. If you have any query regarding NCERT Solutions for Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables Exercise 3.2, drop a comment below and we will get back to you at the earliest.

NCERT Solutions For Class 10 Maths Chapter 2 Ex 2.2

March 6, 2026

Get Free NCERT Solutions for Class 10 Maths Chapter 2 Ex 2.2 PDF. Polynomials Class 10 Maths NCERT Solutions are extremely helpful while doing homework. Exercise 2.2 Class 10 Maths NCERT Solutions were prepared by Experienced LearnCBSE.in Teachers. Detailed answers of all the questions in Chapter 1 maths class 10 Polynomials Exercise 2.2 provided in NCERT TextBook.

Topics and Sub Topics in Class 10 Maths Chapter 2 Polynomials:

Section Name	Topic Name
2	Polynomials
2.1	Introduction
2.2	Geometrical Meaning Of The Zeroes Of A Polynomial
2.3	Relationship Between Zeroes And Coefficients Of A Polynomial
2.4	Division Algorithm For Polynomials
2.5	Polynomials
2.6	Summary

You can also download the free PDF of Ex 2.2 Class 10 Polynomials NCERT Solutions or save the solution images and take the print out to keep it handy for your exam preparation.

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Maths
Chapter	Chapter 2
Chapter Name	Polynomials
Exercise	Ex 2.2
Number of Questions Solved	2
Category	NCERT Solutions

NCERT Solutions For Class 10 Maths Chapter 2 Ex 2.2

NCERT Solutions for Class 10 Maths Chapter 2 Polynomials Ex 2.2 are part of NCERT Solutions for Class 10 Maths. Here we have given Maths NCERT Solutions Class 10 Chapter 2 Polynomials Exercise 2.2.

A simple online Degree and Leading Coefficient Calculator which is a user-friendly tool.

Ex 2.2 Class 10 Maths Question 1.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and their coefficients:
(i) x² – 2x – 8
(ii) 4s² – 4s + 1
(iii) 6x² – 3 – 7x
(iv) 4u² + 8u
(v) t² – 15
(vi) 3x² – x – 4
Solution:

Ex 2.2 Class 10 Maths Question 2.
Find a quadratic polynomial each with the given numbers as the sum and product of zeroes respectively:

Solution:

NCERT Solutions for Class 10 Maths Chapter 2 Polynomial (Hindi Medium) Ex 2.2

Download PDF Now – Real Numbers Class 10 Maths NCERT Solutions

NCERT Solutions for Class 10 Maths

We hope the NCERT Solutions for Class 10 Maths Chapter 2 Polynomials Ex 2.2, help you. If you have any query regarding Maths NCERT Solutions Chapter 2 Polynomials Exercise 2.2, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 10 Science Chapter 6 Life Processes

March 6, 2026

NCERT Solutions For Class 10 Science Chapter 6 Life Processes: In this article, you will find all the necessary information regarding NCERT Solutions For Class 10 Science Chapter 6 Life Processes. Students who are planning to build their career stream in the field of medicine can refer to this article as biology plays a major role in the medical field. Candidates having strong command over life processes class 10 NCERT solutions will be able to easily crack the competitive exams like NEET, AIIMS, JIPMER, etc.,

Did you check the Life Process Important Questions which were given in the previous Board Papers?

In this article, we have covered all the important topics in the exercises and each answer comes with a detailed explanation to help the class 10 students to understand concepts better. Read on to find out everything about NCERT class 10 science book activities solutions chapter 6.

NCERT Solutions for Class 10 Science Chapter 6 Life Processes

Before getting into the details of NCERT Solutions For Class 10 Science Chapter 6 Life Processes, let’s have an overview of topics and subtopics under class 10 science chapter 6 activities solutions:

Life Processes
What Are Life Processes?
Nutrition
Respiration
Transportation
Excretion

Free download NCERT Solutions for Class 10 Science Chapter 6 Life Processes PDF in Hindi Medium as well as in English Medium for CBSE, Uttarakhand, Bihar, MP Board, Gujarat Board, and UP Board students, who are using NCERT Books based on updated CBSE Syllabus for the session 2019-20.

NCERT Solutions for Class 10 Science Chapter 6 Intext Questions

Page Number: 95

Question 1
Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans ?
Answer:
In multicellular organisms like humans, all the body cells are not in direct contact with the surrounding environment. Therefore, every cell of the body will not get oxygen as per need by the process of diffusion from the environment. Therefore diffusion is insufficient to meet the oxygen requirements of multicellular organisms.

Question 2
What criteria do we use to decide whether something is alive ?
Answer:
The main criteria used to decide whether something is alive are breathing and respiration. However, living beings also show growth and movement.

Question 3
What are outside raw materials used by an organism ?
Answer:
Any organism uses organic molecules as raw material. Heteroptrophs use food and autotrophs use carbon dioxide, minerals, water and all organisms use oxygen (for respiration) as raw materials.

Question 4
What processes would you consider essential for maintaining life ?
Answer:
Processes essential for maintaining life are :
(i) Nutrition
(ii) Respiration
(iii) Transportation
(iv) Excretion

Page Number: 101

Question 1
What are the differences between autotrophic nutrition and heterotrophic nutrition ?
Answer:

Autotrophic nutrition	Heterotrophic nutrition
(i) In this mode of nutrition an organism makes or synthesizes its own food.	(i) In this mode of nutrition an organism cannot make or synthesize its own food
Organisms use simple inorganic materials like carbon dioxide and water and synthesise their food in presence of sunlight.	(ii) Organisms cannot make their own food from simple inorganic matter and depend on other organisms for their food.
(iii) All green plants and some algae undergo this mode of nutrition.	(iii) All the animals, most bacteria and fungi undergo this mode of nutrition.

Question 2
Where do plants get each of the raw materials required for photosynthesis ?
Answer:
(i) Carbon dioxide : Plants get carbon dioxide from the environment/atmosphere through stomata.
(ii) Water : Plants absorb water from the soil through roots and transport to leaves.
(iii) Sunlight : Plants get sunlight from the sun.
(iv) Chlorophyll : It is present in chloroplast found in green leaves and green parts of plants.

Question 3
What is the role of the acid in our stomach ?
Answer:
Role of acid in our stomach is :
(i) To make acidic medium which is necessary for the activation of the enzyme pepsin.
(ii) To kill bacteria which the food may contain.

Question 4
What is the function of digestive enzymes ?
Answer:
The food we eat is complex in nature, i.e., it contains complex molecules. Digestive enzymes break down these complex molecules into smaller simpler molecules so that they can be absorbed by the walls of the intestine.

Question 5
How is the small intestine designed to absorb digested food ?
Answer:
The small intestine is designed to provide maximum area for absorption of digested food and its transfer into the blood for its circulation into the body. For this the inner lining of the small intestine has numerous finger-like projections called villi. The villi are richly supplied with blood vessels which take the absorbed food to each and every cell of the body.

Page Number: 105

Question 1
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration ?
Answer:
Aquatic organisms use oxygen dissolved in surrounding water. Since air dissolved in water has fairly low concentration of oxygen, the aquatic organisms have much faster rate of breathing.
Terrestrial organisms take oxygen from the oxygen-rich atmosphere through respiratory organs. Hence, they have much less breathing rate than aquatic organisms.

Question 2
What are the different ways in which glucose is oxidised to provide energy in various organisms ?
Answer:
First step of breakdown of glucose (6 carbon molecules) takes place in the cytoplasm of cells of all organisms. This process yields a three carbon molecule compound called pyruvate.
Further break down of pyruvate takes place in different ways in different organisms.

(i) Anaerobic respiration : The anaerobic respiration in plants (like yeast) produces ethanol and carbon dioxide as end products.
(ii) Aerobic respiration : In aerobic respiration break down of pyruvate takes place in presence of oxygen to give rise three molecules of carbon dioxide and water. The release of energy in aerobic respiration is much more than in anaerobic respiration.
(iii) Lack of oxygen : Sometimes, when there is lack of oxygen especially during physical exercise, in our muscles, pyruvate is converted into lactic acid (3 carbon molecule compound). Formation of lactic acid in muscles causes cramp.

Question 3
How is oxygen and carbon dioxide transported in human beings ?
Answer:
(i) Transport of oxygen : Haemoglobin present in the blood takes up the oxygen from the air in the lungs. It carries the oxygen to tissues which are deficient in oxygen before releasing it.
(ii) Transport of carbon dioxide : Carbon dioxide is more soluble in water. Therefore, it is mostly transported from body tissues in the dissolved form in our blood plasma to lungs. Here it diffuses from blood to air in the lungs.

Question 4
How are the lungs designed in human beings to maximise the area for exchange of gases ?
Answer:
Within the lungs, the air passage divides into smaller and smaller tubes, called bronchi which in turn form bronchioles. The bronchioles terminate in balloon-like structures, called alveoli. The alveoli present in the lungs provide maximum surface for exchange of gases. The alveoli have vary thin walls and contain an extensive network of blood vessels to facilitate exchange of gases.

Page Number: 110

Question 1
What are the components of the transport system in human beings ? What are the functions of these components ?
Answer:
The transport system (circulatory system) in human beings mainly consists of heart, blood and blood vessels.

(i) Function of heart : The heart receives deoxygenated blood from the body parts and pumps it to lungs for enriching with oxygen. It receives purified blood from lungs and pumps it around the body.
(ii) Function of blood : Blood transports oxygen, carbon dioxide, digested food, hormones and nitrogeneous waste like urea. It also protects the body from diseases and regulates the body temperature.
(iii) Function of blood vessels : The blood pushed by the heart flows through the blood vessels (arteries, veins and capillaries) and also comes back to the heart through them.

Question 2
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds ?
Answer:
Separation of oxygenated and deoxygenated blood allows good supply of oxygen to the body. This system is useful in animals that have high energy requirement. Mammals and birds constantly need oxygen to get energy to maintain their body temperature constant.

Question 3
What are the components of the transport system in highly organised plants?
Answer:
In highly organised plants there are two conducting tissues xylem and phloem.
Xylem consists of vessels, tracheids and other xylem tissues. The interconnected vessels and tracheids form a continuous system of water conducting channels reaching all parts of the plant. Xylem carries water and minerals.
Phloem conducts soluble products of photosynthesis from leaves to different parts of the plant body.

Question 4
How are water and minerals transport in plants ? [AICBSE 2015]
Answer:
The roots of a plant have hair called root hair.
The root hair are directly in contact with the film of water in between the soil particles. Water and dissolved minerals get into the root hair by the process of diffusion. The water and minerals absorbed by the root hair from the soil pass from cell to cell by osmosis through the epidermis, root cortex, endodermis and reach the root xylem.

The xylem vessels of the root of the plant are connected to the xylem vessels of its stem.
Therefore the water containing dissolved minerals enters the root xylem vessels into stem xylem vessels. The xylem vessels of the stem branch into the leaves of the plants. So, the water and minerals carried by the xylem vessels in the stem reach the leaves through the branched xylem vessels which enter from the petiole (stalk of the leaf) into each and every part of the leaf. Thus the water and minerals from the soil reach through the root and stem to the leaves of the plants. Evaporation of water molecules from the cells of a leaf creates a suction which pulls water from the xylem cells of roots. The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration.

Question 5
How is food transported in plants ?
Answer:
The movement of food in phloem (or translocation) takes place by utilizing energy. The sugar (food) made in leaves is loaded into the sieve tubes of phloem tissue by using energy from ATR Water now enters the sieve tubes containing sugar by the process of osmosis due to which the pressure in the phloem tissue rises. This high pressure produced in the phloem tissue moves the food to all parts of the plant having less pressure in their tissues. This allows the phloem to transport food according to the needs of the plant.

Page Number: 112

Question 1
Describe the structure and functions of nephrons.
Answer:
Structure of nephron : Each nephron is composed of two parts. First one is a cup-shaped bag at its upper end which is called Bowman’s capsule.
The Bowman’s capsule contains a bundle of blood capillaries which is called glomerulus. One end of the glomerulus is attached to the renal artery which brings the impure blood containing the urea waste into it. These impurities are filtered. The other part of the nephron is coiled. In this part, the substances like sugar (glucose), amino acid, ions and excess water which are required by the body, are reabsorbed. The substance remained in the nephron is mainly urine containing dissolved urea in water which is expelled from the body through urethra from time to time.

Functions of nephron : Filtration of blood takes place in Bowman’s capsule from the capillaries of glomerulus. The filtrate passes into the tubular part of the nephron. This filtrate contains glucose, amino acids, urea, uric acid, salts and water.
Reabsorption : As the filtrate flows along the tubule, useful substances such as glucose, amino acids, salts and water are selectively reabsorbed into the blood by capillaries surrounding the nephron tubule.
Urine : The filtrate which remained after reabsorption is called urine. Urine contains dissolved nitrogenous waste like urea and uric acid, excess salts and water. Urine is collected from nephrons to carry it to the ureter from where it passes into urinary bladder.

Question 2
What are the methods used by plants to get rid of excretory products ?
Answer:
(i) The plants get rid of gaseous products-through stomata in leaves and lenticels in stems.
(ii) The plants get rid of stored solid and liquid waste by the shedding off leaves, peeling off bark and felling off fruits.
(iii) The plants get rid of wastes by secreting them in the form of gums and resins.
(iv) Plants also excrete some waste substances into the soil around them.

Question 3
How is the amount of urine produced regulated ?
Answer:
The amount of urine is regulated by kidney. It depends on the quantity of excess water and wastes dissolved in water.

(i) Quantity of water : When water is abundant in the body tissues, large quantities of dilute urine is excreted out. When water is less in quantity in the body tissues, a small quantity of concentrate urine is excreted.
(ii) Quantity of dissolved wastes : Dissolved wastes, especially nitrogenous wastes, like urea and uric acid and salts are excreted from the body. When there is more quantity of dissolved wastes in the body, more quantity of water is required to excrete them. Therefore, the amount of urine produced increases.
(iii) Hormones : The amount of urine produced is also regulated by certain hormones which control the movement of water and Na+ ions in and out of the nephrons.

NCERT Solutions for Class 10 Science Chapter 6 Textbook Chapter End Questions

Question 1
The kidneys in human beings are a part of the system for
(i) nutrition
(ii) respiration
(iii) excretion
(iv) transportation
Answer:
(iii) Excretion

Question 2
The xylem in plants are responsible for
(i) transport of water
(ii) transport of food
(iii) transport of amino acids
(iv) transport of oxygen
Answer:
(i) Transport of water

Question 3
The autotrophic mode of nutrition requires
(i) carbon dioxide and water
(ii) chlorophyll
(iii) sunlight
(iv) all of the above
Answer:
(iv) All of the above

Question 4
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(i) cytoplasm
(ii) mitochondria
(iii) chloroplast
(iv) nucleus
Answer:
(ii) Mitochondria

Question 5
How are fats digested in our bodies ? Where does this process take place ?
Answer:
Digestion of fats takes place in the small intestine.
Bile juice secreted by the liver poured in the intestine along with pancreatic juice. The bile salts present in the bile juice emulsify fhe large globules of fats. Therefore, by enulsification large globules break down into fine globules to provide larger surface area to act upon by the enzymes.
Lipase enzyme present in the pancreatic juice causes break down of emulsified fats. Glands present in the wall of small intestine secrete intestinal juice which contains lipase enzyme that converts fats into fatty acids and glycerol.

Question 6
What is the role of saliva in the digestion of food ?
Answer:
Saliva contains salivary amylase enzyme that breaks down starch into sugars like maltose.

Saliva keeps the mouth cavity clean and moistens the food that help in chewing and breaking down the big pieces of food into smaller ones.

Question 7
What are the necessary conditions (or autotrophic nutrition and what are its by-products ?
Answer:
Necessary conditions for autotrophic nutrition :
(i) Presence of chlorophyll in the living cells.
(if) Provision of supply of water to green plants or cells of the plant.
(iii) Sufficient sunlight.
(iv) Sufficient supply of carbon dioxide.
By-product of auto tropic nutrition is oxygen.

Question 8
What are the differences between aerobic and anaerobic respiration ? Name some organisms that use the anaerobic mode of respiration.
Answer:

Aerobic respiration	Anaerobic respiration
1. It takes place in the presence of oxygen.	1. It takes place in the absence of oxygen.
2. Complete breakdown of food occurs in aerobic respiration.	2. Partial breakdown of food occurs in anaerobic respiration.
3. The end products in aerobic respiration are carbon dioxide and water.	3. The end products in anaerobic respiration may be ethanol and carbon dioxide (as in yeast plants) or lactic acid (as in animal muscles).
4. Aerobic respiration produces a considerable amount of energy.	4. Much less energy is produced in anaerobic respiration.

Some organisms which use anaerobic respiration are yeast, bacteria etc.

Question 9
How are the alveoli designed to maximise the exchange of gases ?
Answer:
(i) The alveoli are thin walled and richly supplied with a network of blood vessels to facilitate exchange of gases between blood and the air filled in alveoli.
(ii) Alveoli have balloon-like structure. Hence, provide maximum surface for exchange of gases.

Question 10
What would be the consequences of a deficiency of haemoglobin in our bodies?
Answer:
Due to the deficiency of haemoglobin in blood, its oxygen carrying capacity decreases. As a result the production of energy by oxidation will become slower. Therefore, one would fall sick and would feel fatigue most of the time.

Question 11
Describe double circulation in human beings. Why is it necessary ?
Answer:
In our heart blood enters twice and also pumped out twice from the heart. The deoxygenated blood from the body is brought to the right atrium through vena cava from where it is sent to right ventricle. From right ventricle, the blood is pumped to the lungs for oxygenation through pulmonary artery. The oxygenated blood from lungs again enters the left atrium of the heart through pulmonary veins. From left atrium it is send to left ventricle, from where this oxygenated blood is pumped to different parts of body through the arteries. In this way the blood flows through the heart twice, that’s why it is called ‘double circulation’.

Necessity of double circulation: The right side and the left side of the human heart are useful to keep deoxygenated and oxygenated blood from mixing. This type of separation of oxygenated and deoxygenated blood ensures a highly efficient supply of oxygen to the body. This is useful in case of humans who constantly need energy to maintain their body temperature.

Question 12
What are the differences between the transport of materials in xylem and phloem ?
Answer:

Xylem	Phloem
1. Xylem conducts water and dissolved minerals from roots to leaves and other parts.	1. Phloem conducts prepared food material from leaves to other parts of plant in dissolved form.
2. In xylem, the transport of material takes place through vessels and tracheids which are dead tissues.	2. In phloem, transport of material takes place through sieve tubes with the help of companion cells, which are living cells.
3. In xylem upward movement of water and dissolved minerals is mainly achieved by transpiration pull. It is caused due to suction created by evaporation of water molecules from the cells of a leaf.	3. In translocation, material is transferred into phloem tissue using energy from ATP. This increases the osmotic pressure that moves the material in the phloem to tissues which have less pressure

Question 13
Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
Answer:

Alveoli	Nephron
1. Alveoli are functional unit of lungs.	1. Nephrons are functional unit of kidney.
2. A mature lung has about 30 crore alveoli.	2. A kidney has about 10 lakh nephrons.
3. Alveoli provide a wide surface for gaseous exchange.	3. The surface area of a nephron is not much more.
4. The exchange of O₂ and CO₂ takes place through the network of capillaries in alveoli.	4. The Bowman’s capsule in nephron regulates the concentration of water and salts.

NCERT Solutions for Class 10 Science Chapter 6 Life Processes

Life processes: ‘Living being’. Basic concept of nutrition, respiration, transport and excretion in plants and animals.

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Science
Chapter	Chapter 6
Chapter Name	Life Processes
Number of Questions Solved	34
Category	NCERT Solutions

Question 1
How are fats digested in our bodies? Where does this process take place?
Solution:
The small intestine is the site of the complete digestion of carbohydrates, proteins and fats. It receives the secretions of the liver and pancreas for this purpose. The food coming from the stomach is acidic and has to be made alkaline for the pancreatic enzymes to act. Bile juice from the liver accomplishes this in addition to acting on fats. Fats are present in the intestine in the form of large globules, which make it difficult for enzymes to act on them. Bile salts break them down into smaller globules increasing the efficiency of enzyme action. The pancreas secretes pancreatic juice, which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats. The walls of the small intestine contain glands, which secrete intestinal juice. The enzymes present in it finally convert the proteins to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.

Question 2
What is the role of saliva in the digestion of food?
Solution:
When we eat something we like, our mouth ‘waters’. This is actually not only water, but also a fluid called saliva secreted by the salivary glands. Another aspect of the food we ingest is its complex nature. If it is to be absorbed from the alimentary canal, it has to be broken into smaller molecules. This is done with the help of biological catalysts called enzymes. The saliva contains an enzyme called salivary amylase that breaks down starch, which is a complex molecule to give sugar. The food is mixed thoroughly with saliva and moved around the mouth while chewing by the muscular tongue.

More Resources for CBSE Class 10

Question 3
What are the necessary conditions for autotrophic nutrition and what are its byproducts?
Solution:
Carbon and energy requirements of the autotrophic organism are fulfilled by photosynthesis. It is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy. This material is taken in the form of carbon dioxide and water, which is converted into carbohydrates in the presence of sunlight and chlorophyll. Carbohydrates are utilised for providing energy to the plant. The carbohydrates, which are not used immediately, are stored in the form of starch, which serves as the internal energy reserve to be used as and when required by the plant.

Download NCERT Solutions for Class 10 Science Chapter 6 Life Processes PDF

Question 4
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Solution:
The food material taken in during the process of nutrition is used in cells to provide energy for various life processes. Diverse organisms do this in different ways – some use oxygen to breakdown glucose completely into carbon dioxide and water; some use other pathways that do not involve oxygen. In all cases, the first step is the breakdown of glucose, a six-carbon molecule, into a three-carbon molecule called pyruvate. This process takes place in the cytoplasm. Further, the pyruvate may be converted into ethanol and carbon dioxide. This process takes place in yeast during fermentation. Since this process takes place in the absence of air (oxygen), it is called anaerobic respiration. Breakdown of pyruvate using oxygen takes place in the mitochondria. This process breaks up the three-carbon pyruvate molecule to give three molecules of carbon dioxide. The other product is water. Since this process takes place in the presence of air (oxygen), it is called aerobic respiration. The release of energy in this aerobic process is a lot greater than in the anaerobic process.

Question 5
How are the alveoli designed to maximise the exchange of gases?
Solution:
Within the lungs, the passage divides into smaller and smaller tubes, which finally terminate in balloon-like structures, which are called alveoli. The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli contain an extensive network of blood vessels. As we have seen in earlier years, when we breathe in, we lift our ribs and flatten our diaphragm, and the chest cavity becomes larger as a result. Because of this, air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body. During the breathing cycle, when air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.

Question 6
Describe double circulation in human beings. Why is it necessary?
Solution:
The double circulatory system of blood flow refers to the separate systems of pulmonary circulation and the systemic circulation.
The adult human heart consists of two separated pumps, the right side with the right atrium and ventricle which pumps deoxygenated blood into the pulmonary circulation.
The oxygenated blood re-enters the left side of the heart through the pulmonary vein into the left atrium and passes to the left ventricle where it is pumped to the rest of the body. This part of the circulation is called as systemic circulation. This type of circulation is called double circulation. The advantage of a double circulatory system is that blood can be pumped to the rest of the body at a higher pressure.

Multiple Choice Questions (MCQs) [1 Mark each]

Question 1.
Yeast respires anaerobically using sugar as a substrate. Out of the options given below, choose the correct combination of condition and product?

	Condition	Product
(a)	Aerobic	Alcohol
(b)	Aerobic	Lactic acid
(c)	Anaerobic	Alcohol
(d)	Anaerobic	Lactic acid

Answer:
(c) Under an aerobic condition, yeast respires and converts glucose to alcohol and CO₂.

Question 2.
The table shows the percentage composition of four samples of air. Which sample could have been breathed out by a person after vigorous exercise?

Samples	Oxygen	Carbondioxide	Water Vapour
(a)	16	0.3	Saturated
(b)	16	4	Saturated
(c)	21	0.03	Trace
(d)	21	3	Trace

Answer:
(b) This is because rapid aerobic respiration occurs – during vigorous exercise in order to obtain more energy.

Question 3.
Cramps caused during sudden activities are due to the formation of
(a) lactic acid
(b) acetic acid
(c) excess of water
(d) ethanol
Answer:
(a) Lactic acid is formed by the breakdown of pyruvate when oxygen is insufficient in muscles instead of forming C02 and water. Accumulation of excess lactic acid in the muscles causes cramps.

Question 4.
Which of the following plays nose like function in plants?
(a) Flower
(b) Phloem
(c) Stomata
(d) Chlorophyll
Answer:
(c) Stomata are pores which help in the passage of air in the plants.

Question 5.
Which changes occur when a person breathe in deeply?

	Diaphragm Muscle	External Intercostal Muscles
(a)	Contracts	Contract
(b)	Contracts	No change
(c)	Relaxes	Contract
(d)	Relaxes	Relax

Answer:
(a) When a person breathes deeply the external intercostal muscles contract causing the rib cage to swing up and out. Also, the diaphragm contracts and flattens causing the thoracic cavity to increase in volume and decrease in pressure.

Question 6.

The diagram given above shows part of the lining of the human trachea. What is the function of X?
(a) Gaseous exchange
(b) Mucus removal
(c) Phagocytosis
(d) Secretion of mucus
Answer:
(b) The cilia (X) of the cells lining the air passages move in a sweeping motion to keep the air passages clean. The constant action of these cilia carry mucus and debris upward into the pharynx where they are swallowed.

Question 7.
The table given below shows the percentage composition of a gas in inspired and in expired air.

%Composition
Inspired Air	Expired Air
21.0	16.0

What is the gas?
(a) Carbon dioxide
(b) Nitrogen
(c) Oxygen
(d) Water vapour
Answer:
(c) The gas is oxygen as atmospheric air has approximately 21% of oxygen

NCERT Solutions for Class 10 Science Chapter 6 Life Processes (Hindi Medium)

Class 10 Science Life Processes Mind Map

Nutrition
Nutrition is the process by which source of energy (food) is transferred from outside the body of the organism to the inside. Most of the food sources are also carbon-based on Earth and depending on the complexity of these carbon sources different organisms use different kinds of nutritional processes.
Autotrophic Nutrition: Carbon and energy requirements of the autotrophic organism are fulfilled by photosynthesis.

It is the process by which autotrophs convert carbon dioxide & water into carbohydrate in the presence of sunlight and chlorophyll. Oxygen is the byproduct.
The following events occur during this process:
Absorption of light energy by chlorophyll.
Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
Reduction of carbon dioxide to carbohydrates.

Heterotrophic Nutrition: Heterotrophs depend on other organisms for their nutrition.

Saprophytes: They break-down the food material outside the body and then absorb it, also termed as extra-cellular digestion. E.g. fungi like bread moulds, yeast, mushrooms etc.
Parasites: Derive nutrition from plants or animals without killing them. E.g. cuscuta (amar-bel), ticks, lice, leeches, tape-worms etc.
Holozoic nutrition: These organisms take in whole material & break it down inside their bodies. E.g. cow, deer, lion, tiger, humans etc. What can be taken in and broken down depends on body design and functioning

Respiration
It is the process by which organism uses the food material to produce energy. Diverse organisms do this in different ways:

Energy released during cellular respiration is immediately used to synthesise ATP which is used to fuel all other activities in the cell. Aerobic organisms need to ensure that there is sufficient intake of oxygen:
• Plants: Exchange of gases takes place through stomata by simple diffusion. Large inter-cellular spaces ensure that all cells are in contact with air. Direction of diffusion depends upon the environmental conditions and the requirements of the plant. For e.g. CO₂ elimination majorly takes place at night while oxygen release is the major event of the day time.
• Aquatic animals such as fishes take in water through their mouths & force it past the gills where the dissolved oxygen is taken up by blood.
• In human beings, the passage of air can be written as nostril → trachea → bronchi → bronchioles → alveolar sac. The alveoli provide a surface where the exchange of gases can take place. Blood releases the dissolved CO₂ into the alveoli & carries O₂ from alveolar air. Haemoglobin in RBC of blood transport O₂ from lungs to various tissues of the body.

Life Process
The processes which maintain the body functions and are required for the survival of living being are called life processes. Some of the important life processes are nutrition, respiration, transportation, excretion etc.

Nutrition In Human Beings
The alimentary canal is a long tube extending from the mouth to the anus. The nutrition in human being is divided into five steps:
• Ingestion: Intake of food from outside source. Teeth & saliva crush the food to generate the particles of same size & texture. The food is then passed to stomach via oesophagus. The peristaltic movements occur all along the gut which helps in pushing the food forward.
• Digestion: In mouth, salivary amylase helps in carbohydrates digestion. In stomach, pepsin helps in protein digestion. However, small intestine is the main site of complete digestion of carbohydrates, proteins & fats. It receives pancreas and liver secretions. Bile juice emulsifies fats and pancreatic enzymes, trypsin & lipases digest proteins & emulsified fats. It finally converts proteins to amino acids, complex carbohydrates into glucose & fats into fatty acids & glycerol.
• Absorption: The digested food is taken up by the walls of the intestine. The inner lining of the small intestine has numerous finger-like projections called villi which increase the surface area for absorption. Large intestine absorbs water from the unabsorbed food.
• Assimilation: The villi are richly supplied with blood vessels which take the absorbed food to each & every cell of the body, where it is required either for energy, build up or repair.
• Excretion: The waste material is removed from the body via anus which is regulated by anal sphincter.

Transportation
Transportation in Human Beings

Blood consists of fluid medium called plasma in which
the cells are suspended. Plasma transports food, CO₂ & nitrogenous wastes in dissolved form. Oxygen is carried by RBC.
Heart: Heart is the muscular organ made up of cardiac muscles and is as big as our fist. It is composed of four chambers (2 atria & 2 ventricles) to prevent the mixing of oxygenated & deoxygenated blood.
Ventricles are thick wailed as they have to pump the blood to various organs of the body. In addition, valves are also present in heart and veins to prevent the backflow of the blood.

Circulation of blood: Oxygenated blood is carried out from lungs to the left atrium with the help of pulmonary’ veins.

Left atrium contracts to release blood into the left ventricle which relaxes while collecting it. It then pumped out the blood to whole body via aorta.
a Deoxygenated blood from whole body then enters the right atrium via vena cava vein.
Right atrium contracts to pump the blood in right ventricle. It then pumps the blood towards lungs via pulmonary’ artery for oxygenation.

Oxygenation of blood: Invertebrates such as birds, mammals etc which constantly use energy to maintain their body temperature, blood goes through heart twice during each cycle which is known as double circulation.

In contrast, animals like amphibians or many reptiles have three-chambered hearts as they can tolerate some mixing of the oxygenated & de-oxygenated blood streams. They do not use energy for thermoregulation and body temperature depends on the temperature in the environment.
Fishes, on other hand, have only two chambered heart. Blood is pumped to the gills for oxygenation and passes directly to the rest of the body.

Transportation In Plants
There are two main pathways present in plants: xylem pathway- moves water & minerals from the soil & phloem transports products of photosynthesis from leaves (where they are synthesized) to other parts of the plant.
Transport of Water

In xylem tissue, vessels and tracheids of roots, stems & leaves are interconnected to form a continuous system of water-conducting channels reaching all parts of the plant.
At root site, cells actively take up ions from soil which creates concentration gradient. Water then diffuses into the root cells in order to eliminate this gradient.
It provides steady movement of water into root xylem, creating a column of water that is steadily pushed upwards.
However, it is not efficient enough to push water over the heights of tall plants.
So, plants use other method which is known as transpiration to push water upwards. The loss of water in the form of vapour from aerial parts of plant is known as transpiration.
Evaporation of water molecules from the cells of a leaf creates a suction which pulls water from the xylem cells of roots. It also aids in thermoregulation.
Transport of food and other substances
Transport of soluble products of photosynthesis is called translocation.
The translocation takes place in sieve tubes with the help of adjacent companion cells both in upward & downward directions.
It utilizes energy (ATP) in contrast to xylem transport.
Material like sucrose is transferred into phloem tissue using energy from ATP.
It increases osmotic pressure of tissue causing water to move into it.
This pressure moves the material in phloem to tissues which have less pressure.
It allows phloem to move material according to plant’s needs.

Excretion
The biological process involved in removal of harmful metabolic wastes from body is called excretion.
Many unicellular organisms remove these wastes by simple diffusion from body surface into surrounding water. However, complex multi-cellular organisms use specialised organs to perform this function.
Excretion in Human Beings: The excretory system includes pair of kidneys, pair of ureters, urinary bladder & urethra.

Nephrons are the functional units of kidneys. They are the clusters of thin-walled capillaries. Each cluster is associated with cup-shaped end (Bowmans capsule) of a tube that collects the filtered urine.
Substance such as glucose, amino acids, salts & a major amount of water are selectively re-absorbed as the urine flows along the tube. The amount of water depends up on amount of excess water & dissolved waste in the body.
The urine formed in each kidney is carried to urinary bladder by ureter. Urine is stored in urinary bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra.
Excretion in Plants: They get rid of excess water by transpiration.
Many plant waste products are stored in cellular vacuoles.
Waste products may be stored in leaves that fall off.
In addition, some waste products are stored as resins & gums, especially in old xylem.
Lastly, plants excrete some waste substances into the soil around them.

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NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations

March 6, 2026

NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations includes all the important topics with detailed explanation that aims to help students to understand the concepts better. Students who are preparing for their Class 10 exams must go through NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations. All Chapter 1 – Chemical Reactions and Equations Exercise Questions with Solutions to help you to revise complete Syllabus and Score More marks.

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NCERT Solutions for Class 10 Science Chapter 1 – Chemical Reactions and Equations NCERT Solutions for class 10 Science provided herein are designed by our subject matter experts in a simple and precise manner.

NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations

Before getting into the details of NCERT Solutions For Class 10 Science Chapter 1 Chemical Reactions And Equations, let’s have an overview of a list of topics and subtopics under Class 10 Science Chapter 1 Chemical Reactions And Equations:

Chemical Reactions And Equations
Chemical Equations
Types Of Chemical Reactions
Have You Observed The Effects Of Oxidation Reactions In Everyday Life? Y Life?

Free download NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations PDF in Hindi Medium as well as in English Medium for CBSE, Uttarakhand, Bihar, MP Board, Gujarat Board, and UP Board students, who are using NCERT Books based on updated CBSE Syllabus for the session 2019-20.

NCERT Solutions for Class 10 Science Chapter 1 Intext Questions

Page Number: 6

Question 1
Why should a magnesium ribbon be cleaned before burning in air ?
Answer:
Magnesium gets covered with a layer of magnesium oxide when kept in air for a long time. This layer hinders the burning of magnesium. Hence, it is to be cleaned before burning.

Question 2
Write the balanced equation for the following chemical reactions.
(i) Hydrogen + Chlorine → Hydrogen chloride
(ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
(iii) Sodium + Water → Sodium hydroxide + Hydrogen
Answer:
(i) H₂ + Cl₂ → 2HCl
(ii) 3 BaCl₂ + Al₂(SO₄)₃ → BaSO₄ + 2 AlCl₃
(iii) 2Na + 2H₂O → 2NaOH + H₂↑

Question 3
Write a balanced chemical equation with state symbols for the following reactions :
(i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.
(ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.
Answer:
(i) BaCl₂ (aq) + Na₂SO₄ (aq) → BaSO₄(s) + 2NaCl (aq)
(ii) NaOH (aq) + HCl(aq) → NaCl(aq) + H₂O(l)

Page Number: 10

Question 1
A solution of a substance ‘X’ is used for white washing.
(i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.
Answer:
(i) The substance whose solution in water is used for white washing is calcium oxide (or quick lime). Its formula is CaO.

Question 2
Why is the amount of gas collected in one of the test tubes in text book Activity 1.7 (i.e., electrolysis of water) double of the amount collected in the other? Name this gas. [CBSE 2015 (Delhi)]
Answer:
In Activity 1.7, water is electrolysed to give H₂ gas at one electrode and O₂ gas at the other electrode.
2H₂O(l) → 2H₂(g) + O₂(g)
Thus two molecules of water on electrolysis give two molecules of hydrogen gas and one molecule of oxygen gas or in other words the amount of hydrogen gas collected would be double than that of oxygen gas.

Page Number: 13

Question 1
Why does the colour of copper sulphate solution change when an iron nail is dipped in it ?
OR
An iron nail is dipped in the solution of copper sulphate for about 30 minutes. State the change in colour observed. Give reason for the change. [CBSE 2015 (Delhi)]
Answer:
When an iron nail is dipped in copper sulphate solution, the displacement reaction takes place. The colour of copper sulphate solution fades due to the formation of light green solution of iron sulphate.

Question 2
Give an example of a double displacement reaction other than the one given in Activity 1.10 (NCERT Text Book).
Answer:
Sodium hydroxide and hydrochloric acid react to form sodium chloride and water.

Question 3
Identify the substances that are oxidised and the substances which are reduced in the following reactions.
(i) 4Na(s) + O₂(g) → 2Na₂O(s)
(ii) CuO (s) + H₂(g) → Cu (s) + H₂O(l)
Answer:
(i) Substances oxidised is Na as it gains oxygen and oxygen is reduced.
(ii) Substances reduced is Cu as hydrogen is oxidised as it gains oxygen.

NCERT Solutions for Class 10 Science Chapter 1 Textbook Chapter End Questions

Question 1
Which of the statements about the reaction below are incorrect ?
2 PbO(s) + C(s) → 2Pb (s) + CO₂(g)
(a) Lead is getting reduced.
(b) Carbon dioxide is getting oxidised.
(c) Carbon is getting oxidised.
(d) Lead oxide is getting reduced.

(i) (a) and (b)
(ii) (a) and (c)
(iii) (a), (b) and (c)
(iv) All
Answer:
(i) (a) and (b)

Question 2
Fe₂O₃ + 2Al → Al₂O₃ + 2Fe
The above reaction is an example of a
(a) combination reaction
(b) double displacement reaction
(c) decomposition reaction
(d) displacement reaction
Answer:
(d) Displacement reaction.

Question 3
What happens when dilute hydrochloric acid is added to iron filings ? Tick the correct answer :
(a) Hydrogen gas and iron chloride are produced.
(b) Chlorine gas and iron hydroxide are produced.
(c) No reaction takes place.
(d) Iron salt and water are produced.
Answer:
(a) Hydrogen gas and iron chloride are produced.

Question 4
What is a balanced chemical equation ? Why should chemical equations be balanced ?
Answer:
A balanced chemical equation has an equal number of atoms of different elements in the reactants and products.
The chemical equations should be balanced to satisfy the law of conservation of mass.

Question 5
Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Answer:
(a) 3H₂ (g) + N₂ (g) → 2NH₃ (g)
(b) H₂S (g) + 3O₂ (g) → SO₂ (g) + 2H₂O(l)
(c) 3BaCl₂ (aq) + Al₂(SO₄)₃ (aq) → 2AlCl₃ (aq) + 3BaSO₄ ↓(s)
(d) 2K (s) + 2H₂O (l) → 2KOH (aq) + H₂ (g)

Question 6
Balance the following chemical equations :
(a) HNO₃ + Ca (OH)₂ → Ca (NO₃)₂ + H₂O
(b) NaOH + H₂SO₄ → Na₂SO₄ + H₂O
(c) NaCl + AgNO₃ → AgCl + NaNO₃
(d) BaCl₂ + H₂SO₄ → BaSO₄ + HCl
Answer:
(a) 2HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + 2H₂O
(b) 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
(c) NaCl + AgNO₃ → AgCl + NaNO₃
(d) BaCl₂ + H₂SO₄ → BaSO₄ + 2HCl

Question 7
Write the balanced chemical equations for the following reactions :
(a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water
(b) Zinc + Silver nitrate → Zinc nitrate + Silver
(c) Aluminium + Copper chloride → Aluminium chloride + Copper
(d) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride
Answer:
(a) Ca (OH)₂ + CO₂ → CaCO₃ + H₂O
(b) Zn + 2AgNO₃ → Zn(NO₃)₂ + 2 Ag
(c) 2Al + 3 CuCl₂ → 2AlCl₃ + 3 Cu
(d) BaCl₂ + K₂SO₄ → BaSO₄ + 2KCl

Question 8
Write the balanced chemical equation for the following and identify the type of reaction in each case :
(a) Potassium bromide (aq) + Barium iodide (aq) → Potassium iodide (aq) + Barium
(b) Zinc carbonate(s) → Zinc oxide (s) + Carbon dioxide (g) bromide(s)
(c) Hydrogen (g) + Chloride (g) → Hydrogen chloride (g)
(d) Magnesium (s) + Hydrochloric acid (aq) → Magnesium chloride (aq) + Hydrogen (g)
Answer:
(a) 2KBr (aq) + Bal₂(aq) → 2Kl(aq) + BaBr₂(s)
Type : Double displacement reaction

(b) ZnCO₃ (s) → ZnO (s) + CO₂ (g)
Type : Decomposition reaction

(d) Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂ (g)
Type : Displacement reaction

Question 9
What does one mean by exothermic and endothermic reactions ? Give examples.
Answer:
Exothermic reactions : Those reactions in which heat is evolved are known as exothermic reactions. An exothermic reaction is indicated by writing “+ Heat”on the products side of an equation.
Example :
(i) C (s) + O₂ (g) → CO₂ (g) + Heat
(ii) N₂ (g) + 3H₂ (g) → 2NH3 (g) + Heat

Endothermic reactions : Those reactions in which heat is absorbed are known as endothermic reactions. An endothermic reaction is usually indicated by writing “Heat” on the product side of a chemical equation.
Examples :
(i) C (s) + 2S (s) → CS₂ (l) – Heat
(ii) N₂ (g) + O₂ (g) → 2NO(g) – Heat

Question 10
Why is respiration considered an exothermic reaction ? Explain.
Answer:
Respiration is an exothermic process because during respiration glucose combines with oxygen in the cells of our body to form carbon dioxide and water along with the production of energy.

Question 11
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Answer:
In a decomposition reaction, a single compound breaks down to produce two or more simpler substances.
For example:

While, in a combination reaction, two or more substances simply combine to form a new substance.
For example:

Question 12
Write one equation each for the decomposition reactions where energy is supplied in the form of heat, light or electricity.
OR
Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity. [CBSE 2015 (Delhi)]
Answer:

Question 13
What is the difference between displacement and double displacement reactions? Write equations for these reactions.
Answer:
In displacement reactions, a more reactive metal displaces a less reactive metal from its solution. For example,
Fe(s) + CuSO₄(aq) → Cu(s) + FeSO₄(aq)
This is a displacement reaction where iron displaces copper from its solution.
In double displacement reactions, two reactants in solution exchange their ions. For example,
AgNO₃(aq) + NaCl (aq) → AgCl(s) + NaNO₃ (aq)
This is a double displacement reaction where silver nitrate and sodium chloride exchange Cl^– and NO₃^– ions between them.

Question 14
In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.
Answer:

Question 15
What do you mean by a precipitation reaction ? Explain by giving examples.
Answer:
A reaction in which an insoluble solid called precipitate is formed that separates from the solution is called a precipitation reaction.
Example : When a solution of iron (III) chloride and ammonium hydroxide are mixed, a brown precipitate of iron (III) hydroxide is formed.

Question 16
Explain the following in terms of gain or loss of oxygen with two examples each:
(a) Oxidation and
(b) Reduction.
Answer:
(a) Oxidation : The addition of oxygen to a substance is called oxidation.
Example :
(i) S(s) + O₂(g) → SO₂(g) (Addition of oxygen to sulphur)
(ii) 2Mg(s) + O₂ (g) → 2MgO(s) (Addition of oxygen to magnesium)

(b) Reduction : The removal of oxygen from a substance is called reduction.
Example: (i) CuO + H2 \(\underrightarrow { Heat }\) Cu + H₂O
Here, copper oxide is being reduced to copper because oxygen gets removed from copper oxide.

(ii) ZnO + C → Zn + CO
Here, zinc oxide is being reduced to zinc because oxygen gets removed from zinc oxide.

Question 17
A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
Answer:
Element ‘X’ is copper (Cu).
The black coloured compound is copper oxide (CuO). The reaction involved is

Question 18
Why do we apply paint on iron articles ?
Answer:
Paint does not allow iron articles to come in contact with air, water and saves iron articles from damage due to rusting.

Question 19
Oil and fat containing food items are flushed with nitrogen. Why ?
Answer:
To keep food items fresh and save from getting oxidised, food items are flushed with nitrogen.

Question 20
Explain the following terms with one example each (a) Corrosion, (b) Rancidity.
Answer:
(a) Corrosion : It is the process in which metals are eaten up gradually by the action of air, moisture or a chemical (such as an acid) on their surface.
Example : When iron is exposed to moist air for a long period of time, its surface acquires a coating of a brown, flaky substance called rust. Rust is mainly hydrated iron (III) oxide [Fe₂O₃.xH₂0].

(b) Rancidity : The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called rancidity.
Rancidity spoils the food materials prepared in fats and oils which have been kept for a considerable time and makes them unfit for eating.
Rancidity can be prevented by adding anti-oxidants to foods containing fats and oils. It can also be prevented by flushing fat and oil containing foods with nitrogen before sealing.

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Science
Chapter	Chapter 1
Chapter Name	Chemical Reactions and Equations
Number of Questions Solved	28
Category	NCERT Solutions

NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations

NCERT Solutions for Class 10 Science (Chemistry) Chapter 1 Chemical Reactions and Equations are part of NCERT Solutions for Class 10 Science. Here we have given Class 10 Science NCERT Solutions Chapter 1.

Question 1
Which of the given statements about the reaction below are incorrect?

a. Lead is getting reduced
b. Carbon dioxide is getting oxidised
c. Carbon is getting oxidised
d. Lead oxide is getting reduced
(i) (a) and (b)
(ii) (a) and (c)
(iii) (a), (b) and (c)
(iv) all
Solution:
(i) (a) and (b)

Question 2

The above reaction is an example of a
(i). Combination reaction
(ii). Double displacement reaction
(iii). Decomposition reaction
(iv). Displacement reaction
Solution:
(iv) Displacement reaction

Question 3
What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer.
a. Hydrogen gas and iron chloride are produced
b. Chlorine gas and iron hydroxide are produced
c. No reaction takes place
d Iron salt and water are produced
Solution:
Hydrogen gas and iron chloride are produced

Download NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations PDF

Question 4
What is a balanced chemical equation? Why should chemical equations be balanced?
Solution:
An equation for a chemical reaction is an equation in which the number of atoms for each element in the reaction and the total charge is the same for both the reactants and the products. In other words, the mass and the charge are balanced on both sides of the reaction.

Question 5
Translate the following statements into chemical equations and then balance them.
a. Hydrogen gas combines with nitrogen to form ammonia
b. Hydrogen sulfide gas burns in air to give water and sulfur dioxide
c. Barium chloride reacts with Aluminium sulfate to give Aluminium chloride and a precipitate of barium sulphate
d. Potassium metal reacts with water to give a potassium hydroxide and hydrogen gas
Solution:
a. 3H₂ + N₂ → 2NH₃
b. 2H₂S + 3O₂ → 2H₂O + 2SO₂
c. 3BaCl₂ + Al₂(SO₄)₃ → 2AlCl₃ + 3BaSO₄
d. 2K + 2H₂O → 2KOH + H₂

Question 6
Balance the following chemical equations.
a. HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + H₂O
b.NaOH + H₂SO₄ → Na₂SO₄ + H₂O
C. NaCl + AgNO₃ → AgCl + NaNO₃
d. BaCl₂ + H₂SO₄ → BaSO₄ + HCl
Solution:
a. 2HNO₃ + 2Ca(OH)₂ → Ca(NO₃)₂ + 2H₂O
b. 6NaOH + 3H₂SO₄ → 3Na₂SO₄ + 6H₂O
C. NaCl + AgNO₃ → AgCI + NaNO₃
d. BaCl₂ + H₂SO₄ → BaSO₄ + 2HCl

Question 7
Write the balanced chemical equations for the following reactions:
(a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water(b) Zinc + Silver nitrate → Zinc nitrate + Silver(c) Aluminium + Copper chloride → Aluminium chloride + Copper(d) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chlorideAnswer:(a) Ca (OH)2 + CO2 → CaCO3 + H2O(b) Zn + 2AgNO3 → Zn(NO3)2 + 2 Ag(c) 2Al + 3 CuCl2 → 2AlCl3 + 3 Cu(d) BaCl2 + K2SO4 → BaSO4 + 2KCl

Question 8
Write the balanced chemical equation for the following and identify the type of reaction of each case.

Solution:
a. 2KBr + BaI₂ → 2KI + BaBr₂ — Double Displacement reaction
b. ZnCO₃ → ZnO + CO₂ — Decomposition reaction
c. H₂ + Cl₂ → 2HCl — Combination reaction
d. Mg + 2HCl → MgCl₂ + H₂ — Displacement reaction

Question 9
What is meant by exothermic and endothermic reactions? Give examples.
Solution:
An exothermic reaction is one that releases heat.
If 1 mole of N₂ molecule reacts with 1 mole of O₂ molecule, the heat of 184 KJ has to be supplied to initiate the reaction to give 1 mole of NO molecule. This means that the bonds between N – N and O – O are so strong that they do not break easily. N₂ has triple covalent bond between the two N atoms. O₂ has a double covalent bond. Thus energy has to be put into the reaction to break the strong bonds. Thus the above reaction is a good example of an endothermic reaction.

Question 10
Why is respiration considered an exothermic reaction?
Solution:
During respiration, glucose combines with oxygen in the cells of our body to form carbon dioxide and water along with the production of energy.
Glucose + oxygen → carbon dioxide + water + energy
It is an exothermic reaction, because energy is produced during this process.

Question 11
Why are decomposition reactions called the opposite of combination reactions? Write equations for decomposition reactions.
Solution:
Essentially, decomposition reactions are the opposite of combination reactions. A compound decomposes (i.e., “splits-up”) into two or more compounds and/or elements. For example, mercury (II) oxide will, decompose into mercury metal and oxygen, upon heating:
2HgO → 2Hg + O₂
Since heat had to be added to make this reaction occur, it is an endothermic reaction. Most decomposition reactions are endothermic. Another example of decomposition reaction is the heating of calcium carbonate (sea shells, chalk):

Question 12
Write one equation each for decomposition reactions in which energy is supplied in the form of heat, light or electricity?
Solution:
When calcium carbonate is heated, it decomposes to give calcium oxide and carbon dioxide:

Question 13
What is the difference between displacement and double displacement reactions? Write relevant equations for the above?
Solution:
The difference between the displacement and double displacement reactions is that in a displacement reaction one element displaces another by virtue of it being more reactive whereas in a double displacement two anions and two cations switch places between two compounds respectively.
For example:
CuSO₄ (aq) + Zn(s) → ZnSO₄ + Cu(s)
Blue copper sulphate solution reacting with solid zinc will give rise to colourless zinc sulphate solution and solid copper. Thus Zn displaces Cu in the salt form. Zn is more reactive than Cu.
An example of double displacement reaction is the reaction between sodium carbonate and calcium chloride, both in aqueous
Solution:
Na₂CO₃ (aq) + CaCl₂ (aq) → CaCO₃ (ppt) + 2NaCl(aq)

Question 14
In the refining of silver, the recovery of silver from silver nitrate solution involves displacement by copper metal. Write down the reaction involved.
Solution:

Question 15
What do you mean by a precipitation reaction? Explain by giving examples:
Solution:
A precipitation reaction is a reaction in which soluble ions in separate solutions are mixed together to form an insoluble compound that settles out of solution as a solid. This insoluble compound is called a precipitate.

An example of a precipitation reaction
Aqueous silver nitrate (AgNO3), when added to a solution containing potassium chloride (KCl), precipitates a white solid, and silver chloride is observed.
AgNO₃ _(aq) + KCl_(aq) → AgCl_(s) + KNO₃_(aq)
The silver chloride (AgCl) has formed a solid, which is observed as a precipitate.

Question 16
A shiny brown colored element ‘X’ on heating in the air becomes black in color. Name the element ‘X’ and the black coloured compound formed.
Solution:
The shiny brown colored element X is copper metal (Cu). When copper metal is heated in air, it forms a black colored compound copper oxide. So, the black colored compound is the copper oxide or copper (II) oxide, CuO.

Question 17
Why do we apply paint on iron articles?
Solution:
Rust is a soft and porous substance, which gradually falls from the surface of an iron object, and then the iron below starts rusting. Thus, rusting of iron (or corrosion of iron) is a continuous process which, if not prevented in time, eats up the whole iron object. So, when we apply paint on iron articles it reduces the rusting of iron.

Question 18
Oil and fat containing food items are flushed with nitrogen. Why?
Solution:
Packaging fat and oil containing foods in nitrogen gas can prevent rancidity. When the fat and oil present in food materials gets oxidised (in air), their oxidation products have an unpleasant smell and taste. When it is surrounded by unreactive gas, nitrogen, there is no oxygen (of air) to cause its oxidation and make it rancid.

Question 19
Explain the following terms with one example each.
a. Corrosion
b. Rancidity
Solution:
a. Corrosion is the process in which metals are eaten up gradually by the action of air, moisture or a chemical on their surface. Corrosion is caused mainly by the oxidation of metals by the oxygen of air.
Example: Rusting of iron is the most common form of corrosion. When an iron object is left in damp air for a considerable period of time, it gets covered with a red-brown flaky substance called ‘rust’. This is called rusting of iron.
b. The condition produced by aerial oxidation of fat and oil in food which is marked by an unpleasant smell and taste is called rancidity.
Example: Rancidity can be retarded by keeping food in a refrigerator.
The refrigerator has a low temperature inside it. When the food is kept in a refrigerator, the oxidation of fat and oil in it is slowed down due to low temperature. So, the development of rancidity due to oxidation is retarded.

Question 20
Why should a magnesium ribbon be cleaned before burning in air?
Solution:
To remove the oxide layer and facilitates rapid burning.

Question 21
Write the balanced equation for the following chemical reactions.
i. Hydrogen + Chloride → Hydrogen chloride
ii. Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
iii. Sodium + water → Sodium hydroxide + Hydrogen
Solution:
i. H₂ + Cl₂ → 2HCl
ii. 3BaCl₂ + Al₂(SO₄)₃ → 3BaSO₄ + 2AlCl₃
iii. 2Na + 2H₂O → 2NaOH + H₂

Question 22
Write a balanced chemical equation and state symbols for the following reactions.
a. Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride
b. Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.
Solution:

Question 23
A solution of a substance ‘X’ is used for white washing.
Name the substance ‘X’ and write its formula.
(i) Write the reaction of the substance ‘X; named in (ii) above with water
Solution:

Question 24
Why does the colour of copper sulphate solution change when an iron nail is dipped into it?
Solution:
In this reaction, iron displaces copper from copper sulphate solution. The deep blue colour of copper sulphate solution fades due to the formation of light green solution of iron sulphate. A red-brown coating of copper metal is formed on the surface of the iron metal. This displacement reaction occurs because iron is more reactive than copper.

Question 25
Identify the substances that are oxidised and the substances that are reduced in the following reactions.
i. 4Na(s) + O₂ (g) → 2Na₂O(s)
ii. CuO(s) + H₂(g) → Cu(s) + H₂O(l)
Solution:
i. 4Na(s) + O₂ (g) → 2Na₂O(s)
Here oxygen is added to sodium. The addition of oxygen is Called oxidation. So the substance that is oxidized is sodium Na.
ii. CuO(s) + H₂(g) → Cu(s) + H₂O(l)

In this reaction, copper oxide (CuO) gives the oxygen required for the oxidation of hydrogen; therefore, copper oxide is the oxidizing agent. Hydrogen is responsible for removing oxygen from copper oxide; therefore, hydrogen is the reducing agent here.

NCERT Solutions for Class 10 Science Chapter 1 (MCQs) [1 Mark each]

Question 1.
When crystals of lead nitrate are heated strongly in a dry test tube
(a) crystals immediately melt
(b) a brown residue is left
(c) white fumes appear in the test tube
(d) a yellow residue is left
Answer:
(b)Pungent smelling, brown fumes are evolved due to NO₂ gas and brown coloured residue of lead oxide (PbO) is left.

Question 2.
A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation? [NCERT Exemplar]
(a) KMnO₄ is an oxidising agent, it oxidises FeSO₄
(b) FeSO₄ acts as an oxidising agent and oxidises KMnO₄
(c) The colour disappears due to dilution, no reaction is involved
(d) KMnO₄ is an unstable compound and decomposes in the presence of FeSO₄ to a colourless compound
Answer:
(a)Potassium permanganate (KMnO₄) in the presence of dil. H₂SO₄, i.e. in acidic medium, acts as a strong oxidising agent. In acidic medium, KMnO₄ oxidises ferrous sulphate to ferric sulphate.

Question 3.
Dilute hydrochloric acid is added to granulated zinc taken in a test tube. The following observations are recorded. Point out the correct observation.
(a) The surface of metal becomes shining
(b) The reaction mixture turns milky
(c) Odour of a pungent smelling gas is recorded
(d) A colourless and odourless gas is evolved
Answer:
(d)Zinc metal reacts with dil. HCl to form zinc chloride and bubbles of colourless and odourless hydrogen gas is evolved.

Question 4.
When a magnesium ribbon is burnt in air, the ash formed is
(a) black
(b) white
(c) yellow
(d) pink
Answer:
(b)When a Mg ribbon is burnt in air, the ash formed is of magnesium oxide which is white in colour.
2Mg(r) + O₂(g) → 2MgO(f)

Question 5.
Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhyd. CuSO₄ and NaCl were added to the beakers A, B and C, respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B whereas, in case of beaker C, the temperature of the solution falls. Which one of the following statements is/are correct?
I. In beakers A and B, exothermic process has occurred.
II. In beakers A and B, endothermic process has occurred.
III. In beaker C, the exothermic process has occurred.
IV. In beaker C, endothermic process has occurred. [NCERT Exemplar]
(a) Only I
(b) Only II
(c) I and IV
(d) II and III
Answer:
(c)As in case of beakers A and B, heat is given out, so temperature became high, hence it is an exothermic reaction while in beaker C, heat is absorbed from water, so temperature falls, hence it is an endothermic process.

Question 6.
Which of the following will be required to identify the gas evolved when dilute hydrochloric acid reacts with zinc metal?
(a) Red litmus paper
(b) pH paper
(c) Lime water
(d) A burning splinter
Answer:
(d)On reacting with dil. HCl, zinc metal forms zinc chloride and hydrogen gas is evolved. Presence of hydrogen gas can be checked by a burning splinter because H₄gas burnt in a splinter with a pop sound.

Question 7.
On immersing an iron nail in CuSO₄ solution for few minutes, you will observe that
(a) no reaction takes place
(b) the colour of solution fades away
(c) the surface of iron nails acquire a black coating
(d) the colour of solution changes to green
Answer:
(b)Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)
Fe is present above in the reactivity series of metals. Hence, Fe displaces Cu from CuSO₄ solution. And the colour of the solution fades away. This is an example of displacement reaction.

Question 8.
What happens when ferrous sulphate crystals are heated? [CCE 2014]
(a) A gas having the smell of burning sulphur is evolved
(b) No gas is evolved
(c) Brown coloured gas is evolved
(d) Colourless and odourless gas is evolved
Answer:
(a)The green colour of ferrous sulphate crystals changes to brownish black ferric oxide and smell of burning sulphur is evolved due to SO₂ and SO₃.

Question 9.
The colour of the precipitate formed when barium chloride solution is mixed with sodium sulphate solution is [CCE 2014]
(a) blue
(b) black
(c) white
(d) green
Answer:
(c)This is an example of a double displacement reaction and a white precipitate of barium sulphate is formed.

Question 10.
How the colour changes when the gases after thermal decomposition of ferrous sulphate come in contact with an acidified solution of potassium dichromate?
(a) Green to orange
(b) Red to colorless
(c) Orange to green
(d) Blue to green

Answer:
(c) The color changes from orange to green due to the formation of iron (III) sulphate

NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations (Hindi Medium)

Class 10 Science Chemical Reactions and Equations Mind Map

Chemical Equation

The representation of chemical reaction by means of symbols of substances in the form of formulae is called chemical equation.
For example N₂ + 3H₂ ⇌ 2NH₃

Balanced Chemical Equation

A balanced chemical equation has equal number of atom of each element participating in the reaction on both left and right hand sides of the reaction.
According to Law of Conservation of Mass, total mass of the elements present in the products of a chemical reaction has to be equal to the total mass of the element present in the reactants.

Balancing Of A Chemical Equation
Total No of Atoms on R.H.S = Total no of Atoms on L.H.S.
Fe₃O₄ T H₂ → Fe + H₂0
[Fe] Fe₃O₂ + H₂ → 3Fe + H₂0
[0] Fe₃O₄ + H₂ → 3Fe + 4H₂0
[H] Fe₃O₄ + 4H₂ → 3Fe + 4H₂0

Oxidation In Everyday Life

Rusting
When iron reacts with oxygen and moisture it forms a red substance called rust.

Corrosion
Metals on coming in contact with oxygen, water, acids or gases presents in air changes its surface. This is called corrosion for e.g. black coating on silver and green coating on copper.
Prevention – painting, galvanization, oiling, greasing

Rancidity
Oil and fats on exposure to air show a change in taste and smell. This property is known as rancidity.
Prevention – adding antioxidants, Vacuum packing, refrigeration, flushing food with nitrogen

Types Of Chemical Reactions

The transformation of chemical substance into a new chemical substance by making and breaking of bonds between different atom is known a chemical reaction.

Combination Reaction
When two elements or one compound and one element or two compounds combine to form a new product.
Foi example
• H₂ + Cl₂ → 2HCl
• Zn + CuS0₄ → ZnS0₄ + Cu
• NaOH + H₂SO₄ → Na₂SO₄ + H₂O

Exothermic Reactions
Reactions producing energy are called exothermic reactions.
Most of the combination reactions are exothermic in nature.
For example : CaO + H₂O → Ca(OH)₂ + Heat

Oxidation
Gain of oxygen or removal of hydrogen is called oxidation eg.
• Zn + O₂ → ZnO
• Mn + HCl → MnCl₂ + H₂

Reduction
Gain of hydrogen or removal of oxygen is called reduction.
e.g. CuO + H₂ → Cu + H₂0

Redox Reactions
A chemical reaction in which both oxidation and reduction takes place simultaneously are called redox reactions.
For example
CuO + H₂ → Cu + H₂O

Decomposition Reaction
When a compound-split into two or more simple products for example

Decomposition reaction require energy either in the form of heat, light or electricity for decomposing the reactions

Endothermic Reactions
Reactions which require energy to occur are known as endothermic reactions.
For example:

Displacement Reactions
It takes place when a more reactive metal displaces a less reactive metal. For Example:
Fe + CuSO₄ → FeSO₄ + Cu

Double Displacement Reactions
In this reactions ions are exchanged between two reactants and forming new compounds.

Precipitation Reaction :
In some reactions, an insoluble mass is formed which is known as precipitate and such reactions are called precipitation reaction.
For Example
Na₂SO₄ + BaCl₂ → 2NaCl + BaSO₄ Precipitate

Features of NCERT Solutions for Class 10 Chapter 1 Science Chemical Reactions and Equations Students can get comprehensive practice of balancing different kinds of equations.

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Chemical Equation

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