Question

Crystals of CuSO₄ are heated in a test tube for some time. 

(a) What is the colour of CuSO₄ crystals:

(i) before heating, and

(ii)after heating?

(b) What is the source of liquid droplets seen on the inner upper side of the test tube during the heating process?

Answer 1

a. 

(i). The colour of CuSO₄ crystals before heating is blue. 

(ii). after heating the colour of CuSO₄ crystals changes to white.

b. The source of liquid droplets seen on the inner upper side of the test tube during the heating process is the water of crystallization present in the formula unit of copper sulphate. These water of crystallization upon heating is removed from the formula unit and gets condensed on the inner upper side of the test tube during the heating process as liquid droplets.