Class 10 Science Chapter 3 Metals and Non-Metals

Class 10 Science Chapter 3 Metals and Non-Metals The answer to each chapter is provided in the list so that you can easily browse throughout different chapters NCERT Class 10 Science Chapter 3 Metals and Non-Metals and select need one.

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Class 10 Science Chapter 3 Metals and Non-Metals

Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 10 Science Chapter 3 Metals and Non-Metals Solutions for All Subjects, You can practice these here…

Metals and Non-Metals

Chapter – 3

GENERAL SCIENCE

TEXTUAL QUESTIONS AND ANSWERS

Page No – 40

Q.1. Give an example of metal which  

(i) is a liquid at room temperature. 

(ii) can be easily cut with a knife. 

(iii) in the best conductor of heat. 

(iv) is a poor conductor of heat. 

Ans :- (i) Mercury.

          (ii) Sodium. 

          (iii) Silver. 

          (iv) Lead 

Q.2. Explain the meanings of malleable and ductile.

Ans :- The property of metals by which they can be beaten into thin sheets is called malleability and this type of metal is called malleable metal. 

The property of metal by which it can be drawn into wires is called ductile. 

Page -46 

Q.1. Why is sodium kept immersed in kerosene oil ? 

Ans :- Sodium metal is very reactive. It reacts vigorously with oxygen and water. A lot of heat is generated in the reaction. It is therefore, stored in kerosene. 

Q.2. Write equation for the reaction of 

(i) iron with steam. 

(ii) calcium and potassium with water.

Ans :- (i) 3Fe   +   4H₂O(g)      →     Fe₃O₄  +   4H₂

               (Iron)                            (Magnetic oxide of iron) 

(ii) Ca + 2H₂O     →     Ca(OH)₂ + H₂ 

      (calcium)               (Calcium hydroxide) 

      2K    +     2H₂O → 2KOH + H₂

    (potassium) (cold)   (potassium hydroxide)

Q.3. Samples of four metals A, B, C and D were takenand added to the following solution one by one. The results obtained have been tabulated as follows : 

MetalIron (II) sulphateCopper (II) sulphateZinc sulphateSilver nitrate
ANo reactionDisplacement
BDisplacementNo reaction
CNo reactionNo reactionNo reactionDisplacement
DNo reactionNo reactionNo reactionNo reaction

Use the table above to answer the following questions about metals A, B, C and D. 

(i) Which is the most reactive metal ? 

(ii) What would you observe if B is added to a solution of copper (II) sulphate ? 

(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity. 

Ans :-  (i) B is the most reactive metal. 

(ii) B is the more reactive than iron which is more reactive than copper. Hence B is more reactive than copper. B will displace copper from its solution. The chemical equation is – 

B + CuSO₄ → Cu + BSO₄

(iii) B > A> C > D 

Q.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.

Ans :- Hydrogen gas is produced when dilute hydrochloric acid is added to a reactive metal. 

Chemical reaction :- Fe + H₂SO₄ → FeSO₄ + H₂ 

Q.5. What would you observe when zinc is added to a solution of iron (II) sulphate ? Write the chemical reaction that takes place.

Ans :- Zinc is more reactive than iron. Therefore zinc replace iron from its solution. The chemical reaction is-

Zn + FeSO₄ → ZnSO₄ +  Fe 

Page -49 

Q.1. (i) Write the electron-dot structures for sodium, oxygen and magnesium. 

Ans :-           

(ii) Show the formation of Na₂O and MgO by the transfer of electrons. 

Ans :-          

(iii) What are the ions present in these compounds ? 

Ans :- In Na₂O, ions present are Na⁺ and O²⁻ In MgO, ions present are Mg²⁺ and O²⁻ 

Q.2. Why do ionic compounds have high melting points? 

Ans :- This is because a considerable amount of energy is required to break the strong interionic attraction. 

Page -53 

Q.1. Define the following terms. 

(i) Mineral. 

(ii) Ore. 

(iii) Gangue.

Ans :- Mineral :- The elements of compounds, which occur naturally in the earth’s crust are known as minerals.

(ii) Ore :- The minerals which contain a very high percentage of a particular metal and the metal can be profitably extracted from it is called ores. 

(iii) Gangue :- Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand etc. called gangue. 

Q.2. Name two metals which are found in nature in the free state. 

Ans :- Gold and platinum. 

Q.3. What chemical process is used for obtaining a metal from its oxide ? 

Ans :- Metal oxide can be converted to metal by a process called reduction. For example, zinc oxide is reduced to metallic zinc by heating with carbon. 

Zno(s) + C(s) → 2Fe(l) + Al₂O₃(s) + Heat 

Page -55 

Q.1. Metallic oxides of zinc, magnesium and copper were heated with the following metals. 

MetalZincMagnesiumCopper
Zinc oxide—–—–—–
Magnesium oxide—–—–—–
Copper oxide—–—–—–

In which cases will you find displacement reactions taking place ? 

Ans :-     

MetalZincMagnesiumCopper
Zinc oxideNoYesNo
Magnesium oxideNoNoNo
Copper oxideYesYesNo

Q.2. Which metals do not corrode easily ? 

Ans :- Gold and platinum. 

Q.3. What are alloys ? 

Ans :- An alloy is a homogeneous mixture of two or more metals, or a metal and a nonmetal. 

EXERCISES 

Q.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. 

Ans :- (d) AgNO₃ solution and copper metal. 

Q.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.

Ans :- (d) All of the above. 

Q.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.  

Ans :- (a) Calcium.

Q.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. 

Ans :- (c) Zinc is more reactive than tin. 

Q.5. You are given a hammer, a battery, a bulls, wires and a switch. 

(a) How could you use them to distinguish between samples of metals and non-metals ?

(b) Assess the usefulness of these tests in distinguishing  between metals and nonmetals. 

Ans :- Metals can be beaten into thin sheets when it strike with a hemmer. But in a non-metal when it strike with a hammer it becomes Powder.

When metals connected into circuit using battery bulb, wires and switch current passes through the circuit and bulb glows while in a non-metal no current will pass through the circuit. 

(b) Hammer is a reliable method because no non-metal can be spread in to sheet because non-metal carbon in the form of graphite is a conductor of electricity. 

Q.6. What are amphoteric oxides ? Give two examples of amphoteric oxides. 

Ans. The oxides which shows the properties of both basic as well as acidic oxides are known as amphoteric oxides. 

Examples :- Aluminium oxide and zinc oxide. 

Q.7. Name two metals which will displace hydrogen from dilute acids, and two metals which will not. 

Ans :- The two metals which will displace hydrogen from dilute acids are Sodium and Magnesium. 

The two metals which will not displace hydrogen from dilute acids are copper and silver. 

Q.8. In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte ? 

Ans :- Anode            –        Impure metal 

          Cathode          –       Pure metal 

          Electroliti       –       Metal salt solution.  

Q.9. Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved 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 ? 

Ans :- (i) Dry litmus paper   –   No, action. 

          (ii) Moist litmus paper – becomes red. 

(b) Write the balanced chemical equation for the reaction taking place. 

S + O₂ → SO₂ + H₂O → H₂SO₃ 

(Sulphurous acid) 

Q.10. State two ways to prevent the rusting of iron. 

Ans :- (i) By painting. 

          (ii) By oiling. 

Q.11. What type of oxides are formed when nonmetals combine with oxygen ? 

Ans :- Acidic oxides or neutral oxides. 

Q.12. Give reasons. 

(a) Platinum, gold and silver are used to make jewellery. 

(b) Sodium, Potassium and lithium are stored under oil. 

(c) Aluminium is 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. 

Ans :- (a) Because they are non-reactive and they have shining surface. 

(b) Sodium, Potassium and lithium react so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil. 

(c) The surface of aluminium covered with a thin layer of oxide. The protective oxide layer prevent the aluminium from further oxidation. 

(d) It is easier to reduce oxides into metal. 

Q.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. 

Ans :- Copper vessels get a green deposit of  copper carbonate. Since Copper Carbonate dissolves in mild acids of lemon or tamarind juice, copper vessels are cleaned. 

Q.14. Differentiate between metal and non-metal on the basis of their chemical properties. 

Ans :-  

MetalsNon-metals
(1) Oxides of metals are basic.(1) Oxides of metals are  are acidic.
(2) Metals react with water to produce metal hydroxide and hydrogen gas.(2) Generally,m non-metals do not react with water.
(3) Metals react with acids and produce metal Salt and hydrogen.(3) Generally non-metals do not react with acids.

Q.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. They 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 ? 

Ans :- Aqua regia, is a freshly prepared mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1; since it dissolves gold. 

Q.16. Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron). 

Ans :- Steel (an alloy of iron) reacts with hot water. The chemical reaction is 

3Fe(s) + 4H₂O → Fe₃O₄ (s) + 4H₂(g) 

                              (hot)

But copper does not react with hot water 

Cu (s) + H₂O  →  No reaction 

                                   (hot)

Therefore copper is used to make hot water tanks. 

See Next Page No Below…

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