Question

Blue crystals of copper sulphate on heating in a dry test tube become colorless. Give reasons

Answer 1

the water of crystallization evaporates out giving cuso4.h2o from fuso4.5h2o...thus the blue colour turns into colourless

Answer 2

Answer:

$CuSO_4.5H_2O\rightarrow CuSO_4+5H_2O$

When we heat $CuSO_4 .5H_2O$ the water molecules evaporate leaving the crystals of $CuSO_4$.

The heat causes blue copper sulphate (also known as hydrated copper sulphate) to decompose forming anhydrous copper sulphate and water. Anhydrous copper sulphate formed is white in colour.