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

Materials Metals and Nonmetals
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NCERT solutions for class 8 science chapter 4 Materials Metals and Nonmetals provided here is one of the most important resources for class 8 students. The metals and nonmetals solutions are given here so that students can clear their doubts easily and learn the chapter in a more efficient way. Students must learn the concepts of metals and nonmetals properly as it will be helpful for them in higher standards.

NCERT Solutions for Class 8 Science Chapter 4 by Swiflearn are by far the best and most reliable NCERT Solutions that you can find on the internet. These NCERT Solutions for Class 8 Science Chapter 4 are designed as per the CBSE Class 8 Science Syllabus. These NCERT Solutions will surely make your learning convenient & fun. Students can also Download FREE PDF of NCERT Solutions Class 8 Chapter 4.

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

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

Solution:
Zinc and phosphorus can be beaten into thin sheets.

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.

Solution:
Option (c) is the correct answer.

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.

Solution:
(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. ( )

Solution:
(a) Generally, non-metals react with acids. (F)
(b) Sodium is a very reactive metal. (T)

(c) Copper displaces zinc from zinc sulphate solution. (F)
(d) Coal can be drawn into wires. (F)

5. Some properties are listed in the following Table. Distinguish between
metals and non-metals on the basis of these properties.
Properties                           Metal           Non-metals
1. Appearance
2. Hardness
3. Malleability
4. Ductility
5. Heat Conduction
6. Conduction of
Electricity

Solution: Refer pdf.

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.

Solution:
(a) Aluminium is highly malleable and can be easily beaten in sheets. Aluminium is also soft and does not react with food items. That 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. On the passage of electric current they become hot and warm the water.
(c) The reactivity of copper is less than that of zinc. That is why it cannot displace zinc from its solution.
(d) Sodium and potassium are highly reactive metals, so they are stored in kerosene.

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

Solution:
No, we cannot store lemon pickle in an aluminium utensil. Aluminium is a metal and reacts readily with acids to produce hydrogen. So, when aluminium comes in contact with lemon, which is acidic, hydrogen will be produced and the pickles 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

Solution:
A                                                         B
Gold                                                 Jewellery
Iron                                                  Machinery
Aluminium                                       Wrapping food
Carbon                                               Fuel
Copper                                             Electric wire
Mercury                                           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.

Solution:
(a) No reaction will take place because copper is very less reactive.
(b) Iron is more reactive than copper. So iron will replace copper from its solution and brown
coating of copper will be deposited on the iron nails. Also, the blue colour turns green.
Fe + CuSO4 → FeSO4 + Cu

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.

Solution:
(a) Saloni can find the nature of the gas by using a wet litmus paper. If the gas turns the blue litmus paper into red, then the gas is acidic in nature whereas if turns the red litmus into blue, it is basic.
(b) Carbon + Oxygen → Carbon dioxide
C + O2 → CO2

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?

Solution:
For polishing, the gold jewellery is dipped into an acidic solution called aqua regia (a mixture of hydrochloric acid and nitric acid). 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.

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