Lakhmir Singh Chemistry Class 10 Solutions Metals And Non-metals<\/span><\/strong><\/h2>\nLakhmir Singh Chemistry Class 10 Solutions Page No:131<\/strong><\/span><\/p>\nQuestion 1:<\/strong><\/span>
\nName one metal and one non-metal which exist in liquid state at room temperature.
\nSolution :<\/strong><\/span>
\nMetal – Mercury.
\nNon metal – Bromine.<\/p>\nQuestion 2:<\/strong><\/span>
\nWhy are metals called electropositive elements whereas non-metals are called electronegative elements ?
\nSolution :<\/strong><\/span>
\nMetals are electropositive elements because they can form positive ions by losing electrons.
\nNon-metals are electronegative elements because they can form negative ions by gaining electrons.<\/p>\nQuestion 3:<\/strong><\/span>
\n(a) Name the most abundant metal in the earth’s crust.
\n(b) Name the most abundant non-metal in the earth’s crust.
\nSolution :<\/strong><\/span>
\n(a) Aluminium.
\n(b) Oxygen.<\/p>\nLakhmir Singh Chemistry Class 10 Solutions <\/strong>Page No:132<\/strong><\/span><\/p>\nQuestion 4:<\/strong><\/span>
\nName one metal which has a low melting point.
\nSolution :<\/strong><\/span>
\nCesium.<\/p>\nQuestion 5:<\/strong><\/span>
\nName the metal which is the poorest conductor of heat.
\nSolution :<\/strong><\/span>
\nLead.<\/p>\nQuestion 6:<\/strong><\/span>
\nState whether the following statement is true or false :
\nNon-metals react with dilute acids to produce a gas which burns with a ‘pop’ sound.
\nSolution :<\/strong><\/span>
\nFalse.<\/p>\nQuestion 7:<\/strong><\/span>
\nFrom amongst the metals sodium, calcium, aluminium, copper and magnesium, name the metal :
\n(i) which reacts with water only on boiling, and
\n(ii) another which does not react even with steam.
\nSolution :<\/strong><\/span>
\n(i) Aluminium.
\n(ii) Copper.<\/p>\nQuestion 8:<\/strong><\/span>
\nWhat changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails dipped in copper sulphate solution for about 30 minutes ?
\nSolution :<\/strong><\/span>
\nIron nail gets covered with a red-brown coating of copper metal; The blue colour of copper sulphate solution fades gradually.<\/p>\nQuestion 9:<\/strong><\/span>
\nWhat is aqua-regia ? Name two special metals which are insoluble in common reagents but dissolve in aqua-regia.
\nSolution :<\/strong><\/span>
\nAqua-regia is a freshly prepared mixture of one part of concentrated nitric acid and 3 parts of concentrated hydrochloric acid. Gold and platinum dissolve in aqua-regia<\/p>\nQuestion 10:<\/strong><\/span>
\nGive the names and formulae of (a) two acidic oxides, and (b) two basic oxides.
\nSolution :<\/strong><\/span>
\n(a) Carbon dioxide and sulphur dioxide.
\n(b) Sodium oxide and magnesium oxide.<\/p>\nQuestion 11:<\/strong><\/span>
\nWhat name is given to those metal oxides which show basic as well as acidic behaviour ?
\nSolution :<\/strong><\/span>
\nAmphoteric oxides.<\/p>\nQuestion 12:<\/strong><\/span>
\nName two metals which form amphoteric oxides.
\nSolution :<\/strong><\/span>
\nAluminium and zinc.<\/p>\nQuestion 13:<\/strong><\/span>
\nA copper coin is kept immersed in a solution of silver nitrate for some time. What will happen to the coin and the colour of the solution ?
\nSolution :<\/strong><\/span>
\nCopper coin will get a shining greyish white coating of silver metal. The color of the solution will turn blue.<\/p>\nQuestion 14:<\/strong><\/span>
\nWhich property of copper and aluminium makes them suitable :
\n(a) for making cooking utensils and boilers ?
\n(b) for making electric wires ?
\nSolution :<\/strong><\/span>
\n(a) High thermal conductivity.
\n(b) High electrical conductivity.<\/p>\nQuestion 15:<\/strong><\/span>
\nWrite the names and formulae of (a) a metal hydride, and (b) a non-metal hydride.
\nSolution :<\/strong><\/span>
\nSodium hydride,Hydrogen sulphide<\/p>\nQuestion 16:<\/strong><\/span>
\nName the metal which has been placed :
\n(a) at the bottom of the reactivity series
\n(b) at the top of the reactivity series
\n(c) just below copper in the reactivity series
\nSolution :<\/strong><\/span>
\n(a) Gold.
\n(b) Potassium.
\n(c) Mercury.<\/p>\nQuestion 17:<\/strong><\/span>
\nWhich of the two metals is more reactive : copper or silver ?
\nSolution :
\n<\/strong><\/span>Copper.<\/p>\nQuestion 18:<\/strong><\/span>
\n(a) Name one metal which is stored in kerosene oil.
\n(b) Name one non-metal which is stored under water.
\nSolution :<\/strong><\/span>
\n(a) Sodium.
\n(b) White phosphorus.<\/p>\nQuestion 19:<\/strong><\/span>
\nWrite equation for the reaction of :
\n(a) sodium with oxygen
\n(b) magnesium with oxygen
\nSolution :<\/strong><\/span>
\n<\/p>\nQuestion 20:<\/strong><\/span>
\nName two metals which are used :
\n(a) for making electric wires.
\n(b) for making domestic utensils and factory equipment.
\n(c) for making jewellery and to decorate sweets.
\nSolution :<\/strong><\/span>
\n(a) Aluminium and copper.
\n(b) Copper and aluminium.
\n(c) Gold and silver.<\/p>\nQuestion 21:<\/strong><\/span>
\nWhich metal foil is used for packing some of the medicine tablets ?
\nSolution :<\/strong><\/span>
\nAluminium foil.<\/p>\nQuestion 22:<\/strong><\/span>
\nName the non-metal which is used :
\n(a) to convert vegetable oil into vegetable ghee(solid fat).
\n(b) as a rocket fuel (in liquid form).
\n(c) to make electrodes of dry cells.
\n(d) to preserve food materials.
\n(e) in the vulcanisation of rubber.
\nSolution :<\/strong><\/span>
\n(a) Hydrogen.
\n(b) Hydrogen.
\n(c) Carbon.
\n(d) Nitrogen.
\n(e) Sulphur.<\/p>\nQuestion 23:<\/strong><\/span>
\nName one property which is characteristic of (a) metals, and (b) non-metals.
\nSolution :<\/strong><\/span>
\n(a) Metals are malleable.
\n(b) Non-metals are non-malleable.<\/p>\nQuestion 24:<\/strong><\/span>
\nWhat is meant by “brittleness” ? Which type of elements usually show brittleness : metals or non-metals ?
\nSolution :<\/strong><\/span>
\nBrittleness is the property of being brittle i.e. breaking easily.
\nNon-metals show brittleness.<\/p>\nQuestion 25:<\/strong><\/span>
\nWhat will happen if a strip of zinc is immersed in a solution of copper sulphate ?
\nSolution :<\/strong><\/span>
\nWhen a strip of zinc metal is put in copper sulphate solution, then the blue colour of copper sulphate solution fades gradually and red brown coating of copper is deposited on zinc strip.<\/p>\nQuestion 26:<\/strong><\/span>
\nWhat will happen if a strip of copper is kept immersed in a solution of silver nitrate (AgN03<\/sub>) ?
\nSolution :<\/strong><\/span>
\nWhen a strip of copper metal is immersed in silver nitrate solution, the solution gradually becomes blue and a shining greyish-white deposit of silver metal is formed on copper strip.<\/p>\nQuestion 27:<\/strong><\/span>
\nWhat happens when iron nails are put into copper sulphate solution ?
\nSolution :<\/strong><\/span>
\nWhen iron nails are placed in copper sulphate solution, the blue colour of copper sulphate solution fades gradually and red-brown copper metal is formed.<\/p>\nQuestion 28:<\/strong><\/span>
\nHow would you show that silver is chemically less reactive than copper ?
\nSolution :<\/strong><\/span>
\nIf a strip of silver metal is kept immersed in copper sulphate solution for some time, then no reaction occurs. This shows that silver is not able to displace copper from copper sulphate solution.<\/p>\nQuestion 29:<\/strong><\/span>
\nGive reasons for the following :
\nBlue colour of copper sulphate solution is destroyed when iron filings are added to it.
\nSolution :<\/strong><\/span>
\nBlue color of copper sulphate is destroyed because iron displaces copper from copper sulphate solution as iron is more reactive than copper.<\/p>\nLakhmir Singh Chemistry Class 10 Solutions <\/strong>Page No:133<\/strong><\/span><\/p>\nQuestion 30:<\/strong><\/span>
\nName a non-metal having a very high melting point.
\nSolution :<\/strong><\/span>
\nDiamond.<\/p>\nQuestion 31:<\/strong><\/span>
\nWhich property of graphite is utilised in making electrodes ?
\nSolution :<\/strong><\/span>
\nSince graphite is a good conductor of electricity, it is used in making electrodes.<\/p>\nQuestion 32:<\/strong><\/span>
\nName two non-metals which are both brittle and non-ductile.
\nSolution :<\/strong><\/span>
\nSulphur and phosphorus.<\/p>\nQuestion 33:<\/strong><\/span>
\nExplain why, the surface of some metals acquires a dull appearance when exposed to air for a long time.
\nSolution :<\/strong><\/span>
\nThe surface of some metals acquires a dull appearance when exposed to air for a long time because metals form a thin layer of oxides, carbonates or sulphide on their surface by the slow action of various gases present in air.<\/p>\nQuestion 34:<\/strong><\/span>
\nComplete and balance the following equations :
\n
\nSolution :<\/strong><\/span><\/p>\nQuestion 35:<\/strong><\/span>
\nFill in the following blanks with suitable words :
\n(a) Magnesium liberates………………… gas on reacting with hot boiling water.
\n(b) The white powder formed when magnesium ribbon burns in oxygen is of………………………………..
\n(c) Ordinary aluminium strips are not attacked by water because of the presence of a layer of………………………………… on the surface of aluminium.
\n(d) A metal having low melting point is……………………. but a non-metal having very high melting point is………………………
\n(e) Calcium is a…………….. reactive metal than sodium.
\nSolution :<\/strong><\/span>
\n(a)Hydrogen.
\n(b) Magnesium oxide.
\n(c) Aluminium oxide.
\n(d) Sodium; Diamond.
\n(e) Less.<\/p>\nQuestion 36:<\/strong><\/span>
\n(a) What is meant by saying that the metals are malleable and ductile ? Explain with examples.
\n(b) Name two metals which are both malleable and ductile.
\n(c) Which property of iron metal is utilised in producing iron sheets required for making buckets ?
\n(d) Which property of copper metal is utilised in making thin wires ?
\nSolution :<\/strong><\/span>
\n(a) Metals are malleable i.e. they can be beaten into thin sheets with a hammer.
\nExample: Aluminium.
\nMetals are ductile i.e. they can be drawn into thin wires.
\nExample: Copper.
\n(b) Aluminium and copper.
\n(c) Malleability.
\n(d) Ductility.<\/p>\nQuestion 37:<\/strong><\/span>
\n<\/strong><\/span>Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction ?
\nSolution :<\/strong><\/span>
\nSodium and potassium metals react violently with cold water.
\nObservations:
\n1. Metal starts moving over the surface of water making a hissing sound.
\n2. Metal starts reacting with water causing little explosions.
\n3. Soon the metal catches fire and starts burning.<\/p>\nQuestion 38:<\/strong><\/span>
\n(a) With the help of examples, describe how metal oxides differ from non-metal oxides.
\n(b) Which of the following elements would yield : (i) an acidic oxide, (ii) a basic oxide, and (iii) a neutral oxide ?
\nNa, S, C, K, H
\nSolution :<\/strong><\/span>
\n(a)M etal oxides are basic in nature and turn red litmus blue. For example: Magnesium oxide.
\nNon-metal oxides are acidic or neutral in nature. The acidic oxides turn blue litmus red. For example: Carbon dioxide.
\n(b) (i) Acidic oxide: S, C
\n(ii) Basic oxide: Na, K
\n(iii) Neutral oxide: H<\/p>\nQuestion 39:<\/strong><\/span>
\n(a) What are amphoteric oxides ? Give two examples of amphoteric oxides.
\n(b) Choose the acidic oxides, basic oxides and neutral oxides from the following :
\nNa2<\/sub>O ; CO2<\/sub> ; CO ; SO2<\/sub>; MgO ; N2<\/sub>O ; H2<\/sub>O.
\n(c) Which of the following are amphoteric oxides :
\nMgO, ZnO, P2<\/sub>O3<\/sub>, Al2<\/sub>O3<\/sub>, NO2<\/sub>
\nSolution :<\/strong><\/span>
\n(a) Those metal oxides which show basic as well as acidic behavior are known as amphoteric oxides.
\nExample: Aluminium oxide and zinc oxide.
\n(b) Acidic oxide – CO 2 , CO, SO 2 and N 2 O; Basic oxide – Na 2 O, MgO; Neutral oxide – H 2 O.
\n(c) ZnO, Al 2 O 3 .<\/p>\nQuestion 40:<\/strong><\/span>
\n(a) What is the nature of the oxide SO2<\/sub> ? What happens when it is dissolved in water ? Write the chemical equation of the reaction involved.
\n(b) What is the nature of the oxide Na2<\/sub>O ? What happens when it is dissolved in water ? Write the chemical equation of the reaction inolved.
\nSolution :<\/strong><\/span>
\n(a) SO2 is acidic in nature. When dissolved in water, it produces sulphurous acid.
\n
\n(b) Na2O is basic in nature. When dissolved in water, it forms an alkali called sodium hydroxide.
\n<\/p>\nQuestion 41:<\/strong><\/span>
\n(a) What type of oxides are formed when non-metals react with oxygen ? Explain with an example.
\n(b) What type of oxides are formed when metals combine with oxygen ? Explain with the help of an example.
\nSolution :<\/strong><\/span>
\n(a) When non-metals react with oxygen, they form acidic oxides or neutral oxides.
\nExample: Carbon reacts with oxygen to form an acidic oxide called carbon dioxide. Hydrogen reacts with oxygen
\n(b)When metals combine with oxygen, they form basic oxides.
\nExample: Sodium reacts with oxygen to form a basic oxide called sodium oxide.<\/p>\nQuestion 42:<\/strong><\/span>
\n(a) Explain why, metals usually do not liberate hydrogen gas with dilute nitric acid.
\n(b) Name two metals which can, however, liberate hydrogen gas from very dilute nitric acid.
\nSolution :<\/strong><\/span>
\nMetals do not liberate hydrogen gas with nitric acid because nitric acid is a strong oxidizing agent. So, as soon as hydrogen gas is formed in the reaction between a metal and dilute nitric acid, the nitric acid oxidises
\nthis hydrogen to water.
\n(b) Magnesium and manganese.<\/p>\nQuestion 43:<\/strong><\/span>
\n(a) How do metals react with hydrogen ? Explain with an example.
\n(b) How do non-metals react with hydrogen ? Explain with an example.
\nSolution :<\/strong><\/span>
\n(a) Most of the metals do not react with hydrogen. Only a few reactive metals react with hydrogen to form metal hydrides. For example: When hydrogen gas is passed over heated sodium, then sodium hydride is formed.
\n(b) Non-metals react with hydrogen to form covalent hydrides. For example: Sulphur combines with hydrogen to form hydrogen sulphide.<\/p>\nQuestion 44:<\/strong><\/span>
\n(a) What happens when calcium reacts with chlorine ? Write an equation for the reaction which takes place.
\n(b) What happens when magnesium reacts with very dilute nitric acid ? Write an equation for the reaction involved.
\nSolution :<\/strong><\/span>
\n(a)Calcium reacts vigorously with chlorine to form an ionic chloride called calcium chloride.
\n
\n(b)Magnesium reacts with very dilute nitric acid to form magnesium nitrate and hydrogen gas.
\n<\/p>\nQuestion 45:<\/strong><\/span>
\n(a) Arrange the following metals in order of their chemical reactivity, placing the most reactive metal first :
\nMagnesium, Copper, Iron, Sodium, Zinc, Lead, Calcium.
\n(b) What happens when a rod of zinc metal is dipped into a solution of copper sulphate ? Give chemical equation of the reaction involved.
\n