Question

32 Crystals of copper sulphate are heated in a test tube for some time,
[3]
(a) What is the colour of copper sulphate crystals before heating and after
heating?
111
(b) What is the source of liquid droplets seen on inner upper side of the test tube
ducing the heating process?
(c) A metal x when dipped in aqueous solution of aluminium sulphate no reaction (1)
is observed whereas when it is dipped in an aqueous solution of ferrous
sulphate the pale green solution furns colourless Identify metal X. Also write
the reaction of X with ferrous sulphate solution
​

Answer 1

Answer:

During this process of heating, it has been observed that before heating crystals of copper sulphate are blue in colour. But after heating, the colour changes from blue to white.

Answer 2

Explanation:

a) The crystals of hydrated copper sulphate salt are blue in colour. When heated, the salt loses its water of crystallization and turns white.

b) The liquid droplets appearing on the cupper side of test tube are the water molecules that evaparak on heating and condense on touching the cooler surface of upper part of the test tube.

c) When metal 'X' is dipped in aqueous solution of aluminium sulphate no reaction is observed, it means it is less reactive than aluminium. But when it is dipped in ferrous sulphate solution, the solution turns from pale green to colourless. so 'X' is more reactive than iron and thus displaces it from its solution.

Therefore, 'X' must be zinc. It reacts with ferrous sulphate to form colourless: zinc Solution by displacing iron.

Zn(s)+FeSO 4(aq)→ZnSO 4 (aq)+Fe(s)