NCERT Solutions Class 10th Science Chapter – 3 Metals and Non-metals
| Textbook | NCERT |
| Class | 10th |
| Subject | Science |
| Chapter | 3rd |
| Chapter Name | Metals and Non-metals |
| Category | Class 10th Science |
| Medium | English |
| Source | Last Doubt |
| NCERT Solutions Class 10th Science Chapter – 3 Metals and Non-metals Question & Answer What are the example of metal and non metal? What are the 17 non-metals? Which are the 11 non-metals? What is called metal? What is metal explain? What are the main types of metals? What are 5 uses of metals? What are metal elements? Is carbon a metal? What are 22 nonmetals? Is A Diamond a metal? What are the 3 types of metals? Is coal a metal? Why are metals called? How metal is made? Why is metal important? Which group is metal? What is the symbol of metal? What is metal and example? |
NCERT Solutions Class 10th Science Chapter – 3 Metals and Non-metals
Chapter – 3
Metals and Non-metals
Question & Answer
Page – 40
| 1. Give an example of a metal which (i) Is a liquid at room temperature? Answer – Mercury is the metal which is liquid at room temperature. (ii) Can be easily cut with a knife? Answer – Sodium and potassium are the metals which can be cut with a knife. (iii) Is the best conductor of heat? Answer – Silver is the best conductor of heat (iv) Is a poor conductor of heat? Answer – Mercury and lead are poor conductor of heat. |
| 2. Explain the meanings of malleable and ductile. Answer – • Metals which can be beaten to sheets are said to be malleable • Metals which can be drawn into thin wires are said to be ductile |
Page – 46
| 1. Why is sodium kept immersed in kerosene oil? Answer – Sodium is a reactive metals, if kept open it will react with oxygen to explore and catch fire. Sodium metal is kept immersed in kerosene to prevent their reaction with oxygen, moisture and carbon dioxide of air. |
| 2. Write equations for the reactions of (i) iron with steam Answer – Iron reacts with steam to form a magnetic oxide of Fe with the liberation of H2. 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g) (ii) calcium and potassium with water Answer – (a) Calcium reacts with water to form calcium hydroxide and hydrogen. Ca(s) + 2H2O(I) → Ca(OH)2(aq) + H2(g) (b) Potassium reacts with cold water violently immediately with evolution of H2 which catches fire. 2K(s) + 2H2O(I) → 2KOH(aq) + 2H2(g) |
| 3. Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows |
| Metal | Iron(II) sulphate | Copper(II) sulphate | Zinc sulphate | Silver Nitrate |
| A | No reaction | Displacement | – | – |
| B | Displacement | – | – | – |
| C | No reaction | No reaction | No reaction | Displacement |
| D | No reaction | No reaction | No reaction | No reaction |
| Use the Table above to answer the following questions about metals A, B, C and D. (1) Which is the most reactive metal? Answer – Metal B is the most reactive as it gives displacement reaction with iron (II) sulphate. (2) What would you observe if B is added to a solution of Copper (II) sulphate? Answer – When metal B is added to copper (II) sulphate solution, a displacement reaction will take place because of which the blue colour of copper (II) sulphate solution will fade and a red-brown deposit of copper will be formed on metal B. (3) Arrange the metals A, B, C and D in the order of decreasing reactivity. Answer – Metal B is the most reactive because it displaces iron from its salt solution. Metal A is less reactive because it displaces copper from its salt solution. Metal C is still less reactive because it can displace only silver from its salt solution and metal D is the least reactive because it cannot displace any metal from its salt solution. Hence, the decreasing order of reactivity of the metals is B > A > C > D. |
| 4. Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4. Answer – Hydrogen gas is liberated when dilute HCl is added to a reactive metal. Fe(s) + H2SO4(aq) → FeSO4(aq) + H2(g) |
| 5. What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes place. Answer – Zinc is more reactive (more electro positive) than iron. Therefore Zinc displaces Iron from its salt solution. The colour of ferrous sulphate is pale green, which turns colourless. FeSO4 + Zn → ZnSO4 + Fe(s) Light green Zinc sulphate(Colourless) |
Page – 49
| 1. (i) Write the electron – dot structures for sodium and oxygen. Answer – Sodium –  Oxygen –  (ii) Show the formation of Na2O and MgO by the transfer of electrons. Answer – Formation of Magnesium oxide – When magnesium reacts with oxygen, the magnesium atom transfers its two outermost electrons to an oxygen atom. By losing two electrons, the magnesium atoms form a magnesium ion (Mg2+) and by gaining two electrons, the oxygen atom forms an oxide ion (O2–). Mg:+  o → MgO Formation of Sodium oxide – Two sodium atoms transfer their 2 outermost electrons to an oxygen atom. By losing two electrons, the two sodium atoms form sodium ions (2Na+). And by gaining two electrons, the oxygen atom forms an oxide ion (O2–).  (iii) What are the ions present in these compounds? Answer – The ions present in sodium oxide compound (Na2O) are sodium ions (2Na+) and oxide ions (O2–). The ions present in Magnesium oxide compound (MgO) are magnesium ions Mg2+ and oxide ions (O2–). |
| 2. Why do ionic compounds have high melting points? Answer – Ionic compounds are the ones which has both positive and negative charges. Hence there will be strong force of attraction between them. This make expenditure of lot of heat to break this force of attraction hence ionic compounds have high melting points. |
Page – 53
| 1. Define the following terms. (i) Mineral (ii) Ore (iii) Gangue Answer – i) mineral – the naturally occuring compounds of elements are known as mineral. ii) ore – the mineral from which an element can be extracted easily and profitably is called an ore. iii) gangue – the impurities present in ore such as sand rock etc is known as gangue. |
| 2. Name two metals which are found in nature in the free state Answer – Gold and platinum are the two metals found in Free State in nature. |
| 3. What chemical process is used for obtaining a metal from its oxide? Answer – Reduction method is used to obtain metal from its oxide. Ex – Zinc oxide is reduced to metallic zinc by Heating with carbon. ZnO + C → Zn + CO Ex – Lead oxide is reduced to lead by heating with carbon PbO +C → Pb + CO |
Page – 55
| 1. Metallic oxides of zinc, magnesium and copper were heated with the following metals. |
| Metal | Zinc | Magnesium | Copper |
| Zinc Oxide | |||
| Magnesium Oxide | |||
| Copper Oxide |
| Answer – A more reactive metal can displace a less reactive metal from its oxide. Among Zinc, Magnesium, and Copper metals, magnesium is the most reactive, copper is the least reactive metal and zinc is less reactive .The displacement reaction will take place in the following cases |
| Metal | Zinc | Magnesium | Copper |
| Zinc Oxide | – | Displacement | – |
| Magnesium Oxide | – | – | – |
| Copper Oxide | Displacement | Displacement | – |
| 2. Which metals do not corrode easily? Answer – Gold and platinum are the metals which do not corrode easily. |
| 3. What are alloys? Answer – An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. |
Exercises Question Answer Page no. 56-57
| Question 1. Which of the following pairs will give displacement reactions? (a) NaCl solution and copper metal (b) MgCl2 solution and aluminium metal (c) FeSO4 solution and silver metal (d) AgNO3 solution and copper metal Answer – (d) AgNO3 solution and copper metal |
| Question 2. Which of the following methods is suitable for preventing an iron frying pan from rusting? (a) Applying grease (b) Applying paint (c) Applying a coating of zinc (d) All of the above Answer – (c) Applying a coating of zinc |
| Question 3. An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be (a) Calcium (b) Carbon (c) Silicon (d) Iron Answer – (a) Calcium |
| Question 4. Food cans are coated with tin and not with zinc because (a) Zinc is costlier than tin. (b) Zinc has a higher melting point than tin. (c) Zinc is more reactive than tin. (d) Zinc is less reactive than tin. Answer – Answer is c. Food cans are coated with tin and not with zinc because Zinc is more reactive that is electro positive than tin. |
| Question 5. You are given a hammer, a battery, a bulb, wires and a switch. (a) How could you use them to distinguish between samples of metals and non-metals? Answer – Metals are malleable and can be easily drown into sheets by hitting with hammer. On the other hand if we beat non-metals they break down and they cannot be drawn into sheets as they are non-malleable. Metals of good conductors of electricity hence they make bulb when you connect metals with a battery, wire and bulb. Similarly If non-metals are bad conductors of electricity chance they fail to lit up the bulb on connecting with wire and battery. (b) Assess the usefulness of these tests in distinguishing between metals and non-metals. Answer – These experiments can be helpful to demonstrate the malleability and electric conductivity of the metals and non-metals |
| Question 5. You are given a hammer, a battery, a bulb, wires and a switch. (a) How could you use them to distinguish between samples of metals and non-metals? |
| Question6. What are amphoteric oxides? Give two examples of amphoteric oxides Answer – Oxides that react with both acids and bases to form salt and water are known as amphoteric oxides. Examples: PbO and Al2O3. • Amphoteric oxides are the one which reacts with both acids and bases to form salt and water.Examples: Lead oxide – PbO and Aluminium oxide – Al2O3. |
| Question 7. Name two metals which will displace hydrogen from dilute acids, and two metals which will not. Answer – Zinc (Zn) and Magnesium (Mg) are the two metals which will displace Hydrogen from dilute acids as they are very reactive metals. Gold (Au) and Silver (Ag) are the metals which will not replace Hydrogen from dilute acids as these metals are less reactive. |
| Question 8. In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte? Answer – In the process of electrolytic refining of metal called ‘M’, An impure and thick block of metal M. is considered as anode, Thin strip or wire of pure metal M is taken as cathode. A suitable salt solution of metal M is considered as the electrolyte. |
| Question9. Pratyush took sulphur powder on a spatula and heated it. He collected the gas e volved by inverting a test tube over it, as shown in figure below. (a) What will be the action of gas on (i) dry litmus paper? (ii) moist litmus paper? Answer – a) When sulphur powder is burnt in the air sulphur-di-oxide is formed. (i) Sulphur-di-oxide does not have any effect on dry litmus paper. (ii) Sulphur-di-oxide turn the moist litmus paper from blue to red as contact of SO2 with water turns to sulfurous acid. (b) Write a balanced chemical equation for the reaction taking place. Answer – S(s) + O2(g) → SO2(g) SO2(g) + H2O →H2SO3 |
| Question 10. State two ways to prevent the rusting of iron. Answer – Iron can be prevented from rusting by coating the surface of the iron with rust proof paints By applying Oil/grease on the surface of iron objects as it will prevent the iron surface to get in contact with air consisting of moisture. |
| Question 11. What type of oxides are formed when non-metals combine with oxygen? Answer – When non-metals combine with oxygen it forms either acidic or neutral oxides. Ex: N2O5 or N2O3 is an acidic oxide; CO is a neutral oxide. |
| (a) Platinum, gold and silver are used to make jewellery. Answer – Platinum, gold and silver are used to make jewellery for these metals are very less reactive hence they are not affected by air, water or most chemicals. These metals have a lot of luster and they are malleable and ductile in nature and also high corrosion resistance in nature. (b) Sodium, potassium and lithium are stored under oil. (c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking. (d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction |
| Question 13. You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels. Answer – Tarnished copper vessels being cleaned with lemon or tamarind because this sour substance contains acids which dissolve the coating of copper oxide or basic copper carbonate present on the surface or tarnished copper vessels. This makes them shining red-brown again. Hence they are very effective in cleaning tarnished copper vessels. |
| Question 14. Differentiate between metal and non-metal on the basis of their chemical properties. Answer –
|
| Question 15. A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used? Answer – Goldsmith used the solution called Aqua regia which is called as royal water in Latin. It is the mixture of concentrated Hydrochloric acid and concentrated nitric acid in the ratio of 3:1. Aqua regia is capable of dissolving noble metals like gold and platinum. When upper-layer of dull gold ornament is dissolved they lose their weight. |
| Question 16. Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron). Answer – Copper is used to make hot water tanks and not steel (an alloy of iron) because copper does not reacts with either water or steam whereas iron reacts with steams to corrode the tank. |
| NCERT Solution Class 10th Science All Chapters Question & Answer |
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