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NCERT Solutions for Class 8 Science Chapter 4 Materials: Metals and Non-Metals

Gurmeet Kaur

Get the NCERT Solutions for Class 8 Science Chapter 4 - Materials: Metals and Non-Metals from here to prepare for your tests and exams to be held in 2021-2022. You can find here the appropriate answers to the questions given in chapter 4 of the latest NCERT Book for Class 8 Science. With the help of these NCERT Solutions, you will definitely understand all the concepts clearly and score the desired marls in your Class 8 Science Exam.

NCERT Solutions for Class 8 Science Chapter 4 - Materials: Metals and Non-Metals

Exercises

1. Which of the following can be beaten into thin sheets?
(a) Zinc

(b) Phosphorus

(c) Sulphur 

(d) Oxygen

Answer: (a) Zinc

2. Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.

Answer: (c) Generally, metals are ductile.

3. Fill in the blanks:
(a) Phosphorus is a very _________non-metal.
(b) Metals are ________ conductors of heat and _________.
(c) Iron is ________reactive than copper.
(d) Metals react with acids to produce _________gas.

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Answer:

(a) Phosphorus is a very reactive non-metal.
(b) Metals are good conductors of heat and electricity.
(c) Iron is more reactive than copper.
(d) Metals react with acids to produce hydrogen gas.

4. Mark 'T' if the statement is true and 'F' if it is false.

(a) Generally, non-metals react with acids. ( )

(b) Sodium is a very reactive metal. ( )

(c) Copper displaces zinc from zinc sulphate solution. ( )

(d) Coal can be drawn into wires. ( )

Answer:

(a) False

(b) True

(c) False

(d) False

5. Some properties are listed in the following Table. Distinguish between metals and non-metals on the basis of these properties.

Properties

Metals

Non-metals

1. Appearance
2. Hardness
3. Malleability
4. Ductility
5. Heat Conduction
6. Conduction of Electricity

   

Answer:

Properties

Metals

Non-metals

1. Appearance

Lustrous

Dull

2. Hardness

Hard

Soft

3. Malleability

Can be beaten into thin sheets

Cannot be beaten into thin sheets

4. Ductility

Can be drawn into wires

Cannot be drawn into wires

5. Heat conduction

Good conductors of heat

Poor conductors of heat

6. Conduction of electricity

Good conductors of electricity

Poor conductors of electricity

6. Give reasons for the following.
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods for heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.

Answer:

(a) Aluminium foils are used to wrap food items because aluminium metal is malleable and it can be beaten into thin sheets.

(b) Immersion rods for heating liquids are made up of metallic substances because metals are good conductors of heat and electricity.

(c) Since only a more reactive metal can displace a less reactive metal from its salt in aqueous solution therefore copper which is less reactive than zinc cannot displace zinc from its salt solution.

(d) Sodium and potassium are stored in kerosene because they are highly reactive that they vigorously react with oxygen and moisture present in the air.

7. Can you store lemon pickle in an aluminium utensil? Explain.

Answer:

No, lemon pickle cannot be stored in aluminium utensils because lemon pickle contains acids that can react with aluminium metal to produce hydrogen gas. Therefore, the pickle will be spoiled.

8. Match the substances given in Column A with their uses given in Column B.

A

B

(i) Gold

(a) Thermometers

(ii) Iron

(b) Electric wire

(iii) Aluminium

(c) Wrapping food

(iv) Carbon

(d) Jewellery

(v) Copper

(e) Machinery

(vi) Mercury

(f) Fuel

Answer:

A

B

(i) Gold

(d) Jewellery

(ii) Iron

(e) Machinery

(iii) Aluminium

(c) Wrapping food

(iv) Carbon

(f) Fuel

(v) Copper

(b) Electric wire

(vi) Mercury

(a) Thermometers

9. What happens when

(a) Dilute sulphuric acid is poured on a copper plate?

(b) Iron nails are placed in copper sulphate solution?

Write word equations of the reactions involved.

Answer:

(a) No reaction takes place when dilute sulphuric acid is poured on a copper plate because copper is less reactive.

(b) When iron nails are placed in copper sulphate solution iron being more reactive displaces copper from copper sulphate solution. In this reaction, the blue colour of copper sulphate fades and copper gets deposited on iron nail.

Iron + Copper Sulphate  → Iron Sulphate + Copper

10. Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.

(a) How will she find the nature of the gas?

(b) Write down word equations of all the reactions taking place in this process.

Answer:

(a) Add a few drops of water to the test tube containing gas. Now, cover the test tube and shake it well. Now, test the solution with the blue litmus paper and the red litmus paper. The blue litmus paper will be turned red. This shows that the gas is acidic in nature.

(b) Charcoal reacts with oxygen to form carbon dioxide gas.
Carbon (from Charcoal) + Oxygen → Carbon dioxide

11. One day Reeta went to a jeweller's shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?

Answer:

To polish the gold jewellery, it is dipped into an acidic solution called aqua regia (a mixture of hydrochloric acid and nitric acid). On dipping the gold into this acidic solution, the outer layer of gold dissolves and the inner shiny layer appears. Thus, the removal of the outer layer of gold causes a slight loss in its weight.

Download NCERT Solutions for Class 8 Science Chapter 4 in PDF

Also check the NCERT Books and NCERT Solutions for all major subjects of Class 8:

NCERT Books for All Subjects of Class 8 (Latest Editions for 2021-2022)

NCERT Solutions for All Subjects of Class 8 (Updated for 2021-2022)

 

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