Question

Crystals of Copper sulphate are heated for some time. What is the color of the crystals before and after heating?

Answer 1

Heating of Copper sulphate Crystals:

When Copper sulfate crystals are heated for some time they tend to lose their water of crystallization and change their color.

Before Heating:

Before heating, the copper sulfate crystals are blue as they are in hydrated form i.e. ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$.

After Heating:

After heating, the copper sulfate crystals turn white as they lose their water of crystallization.

The reaction involved is as follows,

${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}\left(\mathrm{s}\right)\stackrel{\mathrm{Heat}}{\to }{\mathrm{CuSO}}_4\left(\mathrm{s}\right)+5{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$

Hence, blue and white is the color of the crystals before and after heating of crystals of Copper sulphate respectively.