Metals and Non-metals NCERT Solution, study material, CBSE Notes

NCERT Solution: Metals and Non-metals

Give an example of a metal which
(i) is a liquid at room temperature.

Answer: Mercury

Give an example of a metal which

(ii) can be easily cut with a knife.

Sodium can be easily cut with a knife

Give an example of a metal which

(iii) is the best conductor of heat.

Silver is the best conductor of heat.

Give an example of a metal which

(iv) is a poor conductor of heat.

Mercury and Lead are poor conductor of heat

Explain the meanings of malleable and ductile.

Malleable:Substances that can be beaten into thin sheets are called malleable. For example, most of the metals are malleable.
Ductile: Substances that can be drawn into thin wires are called ductile. For example, most of the metals are ductile.

Why is sodium kept immersed in kerosene oil?

Sodium is high reactive element. If it is kept in open it can explosively react with oxygen to catch fire. Hence to prevent accidental damage sodium is immersed in kerosene oil.

Write equations for the reactions of
(i) iron with steam
(ii) calcium and potassium with water

(i) 3Fe (s) + 4H₂O (g) → Fe₃O₄ (aq) + 4H₂ (g)

(ii) Ca (s) + 2H₂O (l) → Ca(OH)₂ (aq) + H₂ (g) + Heat
2K (s) + 2H₂O (l) → 2KOH (aq) + H₂ (g) + Heat

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	Cooper (II) sulphate	Zinc sulphate	Silver nitrate
A	No reaction	Displacement
B	Displacement		No reaction
C	No reaction	No reaction	No reaction	No reaction
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.
(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.

Solution:

A + FeSO₄ → No reaction, i.e., A is less reactive than iron

A + CuSO₄ → Displacement, i.e., A is more reactive than copper

B + FeSO₄ → Displacement, i.e., B is more reactive than iron

B + ZnSO₄ → No reaction, i.e., B is less reactive than zinc

C + FeSO₄ → No reaction, i.e., C is less reactive than iron

C + CuSO₄ → No reaction, i.e., C is less reactive than copper

C + ZnSO₄ → No reaction, i.e., C is less reactive than zinc

C + AgNO₃ → Displacement, i.e., C is more reactive than silver

D + FeSO₄/CuSO₄/ZnSO₄/AgNO₃ → No reaction, i.e., D is less reactive than iron, copper, zinc, and silver

(i) B is most reactive metal.
(ii) B will displace copper from copper sulphate.
(iii) Arrangement of metals in the order of decreasing reactivity B>A>C>D.