Question

why does blue colour copper sulphate solution fade when zinc is added to it

Answer 1

it is a example of displacement reaction

copper is weak than zinc
that's why the copper sulphate of blue colour get disappear when zinc is added in solution

Answer 2

When Zinc is added to aqueous Copper sulphate solution (which is blue in colour), copper is slowly displaced by Zinc, from its solution.

This leads to the formation of Zinc sulphate which is colourless.

The chemical equation of the above process is:

CuSO₄ + Zn -----------> ZnSO₄ + Cu

As the reaction proceeds, Zinc slowly displaces copper from its blue-coloured copper sulphate solution thus forming the colourless Zinc sulphate solution;

Hence we observe that the blue colour slowly fades as the concentration of CuSO₄ decreases.

Hope it helps!!