Question

Crystals of copper sulphate are heated in a test tube for some time. What is the colour of copper sulphate (i) before heating and (ii) after heating ? What is the source of liquid droplets seen on the upper side of the test tube during the heating process?

Answer 1

The colour of hydrated copper sulphate ${CuSO}_4.5H_{2}O$ is blue that turns into while, when heated at high temperature in a test tube, due to loss of water molecules from copper sulphate.

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.