Materials Metals And Non Metals Class 8 NCERT Solutions

Materials Metals and non metals class 8 NCERT Solutions is available below for students to learn its basic principles. The study material focuses on providing in-depth knowledge of the concepts discussed in the chapter. Students can access the free materials for preparing their notes and doing regular revisions. These solutions assist students in writing comprehensive answers to score maximum marks in their paper.

This chapter is an essential segment of the Science syllabus and students must prepare it well. materials metals and non metals class 8 serves as a base for many upcoming advanced chapters prescribed for senior classes. Therefore, these NCERT Solutions of Materials Metals And NonMetals will help them tighten their command on the basics.

Question 1.

Which of the following can be beaten into thin sheets? (a) Zinc
(b) Phosphorus
(c) Sulphur
(d) Oxygen
Answer:
(a) Zinc

Question 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

Question 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.
Answer:
(a) reactive
(b) good, electricity
(c) more
(d) hydrogen

Question 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

Question 5.

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

• Appearance
• Hardness
• Malleability
• Ductility
• Heat Conduction
• Conduction of Electricity

Answer:
Metals

• Appearance: Have metallic lustre
• Hardness: Hard
• Malleability: Malleable
• Ductility: Ductile
• Heat Conduction: Good conductors
• Conduction of Electricity: Good conductors

Non-metals

• Appearance: Dull
• Hardness: Soft
• Malleability: Non-malleable
• Ductility: Non-ductile
• Heat Conduction: Bad conductors
• Conduction of Electricity: Bad conductors/Insulators

Question 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 is highly malleable and can be easily beaten into sheets to make its foil for wrapping purposes. It is also soft and does not react with food items, which is why aluminium foils are used to wrap food items.

(b) Immersion rods are made up of metallic substances because metals are good conductors of heat and electricity. They get hot very quickly on the passage of electric current and warm the water.

(c) Copper is less reactive than zinc, so it cannot displace zinc from its solution.

(d) Sodium and potassium are highly reactive, so they are stored in kerosene to prevent them from reacting with moisture or oxygen in the air.

Question 7.

Can you store the lemon pickle in an aluminium utensil? Explain.
Answer:
No, we cannot store lemon pickle in an aluminium utensil because aluminium is a metal, and metals readily react with acids to produce hydrogen. When aluminium comes in contact with lemon, which is acidic, it will react and produce hydrogen, spoiling the pickles.

Question 8.

Match the substances given in column A with their uses given in column B.

A

• Gold
• Iron
• Aluminium
• Carbon
• Copper
• Mercury

B

• Thermometers
• Electric wire
• Wrapping food
• Jewellery
• Machinery
• Fuel

Answer:

• Gold – (iv) Jewellery
• Iron – (v) Machinery
• Aluminium – (iii) Wrapping food
• Carbon – (vi) Fuel
• Copper – (ii) Electric wire
• Mercury – (i) Thermometers

Question 9.

What happens when
(a) Dilute sulphuric acid is poured on a copper plate?
(b) Iron nails are placed in a copper sulphate solution?
Write word equations of the reactions involved.

Answer:
(a) No reaction will take place because copper is very less reactive.

(b) Iron, being more reactive than copper, will replace copper from its solution, and a brown coating of copper will be deposited on the iron nails. The blue colour of the solution turns green.

Word Equation:
Iron + Copper sulphate (solution) → Iron sulphate (solution) + Copper

Question 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 the word equations of all the reactions taking place in this process.

Answer:
(a) She can find the nature of the gas by using a wet litmus paper. If the gas turns blue litmus paper red, it is acidic. Similarly, if it turns red litmus blue, it is basic.

(b)
(i) Carbon + Oxygen → Carbon dioxide
(ii) Carbon dioxide + Lime water → Milky

Question 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. The 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:
The gold jewellery is dipped into an acidic solution called aqua regia (a mixture of hydrochloric acid and nitric acid) for polishing. On dipping the gold jewellery in the acid solution, the outer layer of gold dissolves, and the inner shiny layer appears. This causes a slight loss in its weight.