Question

when we put cuso4 in water, after sometime we find the solution turns blue. why? also, on heating it, what change will occur?

Answer 1

CuSO4 is soluble in water. And when we add CuSO4 in water anhydrous copper sulfate makes a bond with water CuSO4.5H2O which is blue in color. On heating it hydrated Copper sulfate will become again anhydrous copper sulfate which is white in color.

Answer 2

Copper sulphate turns blue when we add it into water. This is because, when we add water to anhydrous copper sulphate with formula $\mathrm{CuSO}_{4}$, it turns to $\bold{\mathrm{CuSO}_{4} .5 \mathrm{H}_{2} \mathrm{O}}$. Here $5 \mathrm{H}_{2} \mathrm{O}$ indicates the water of crystallization.

Due to this the color changes to blue. When we heat this hydrate copper sulphate, it turns to white or colorless. This is because the water of crystallization comes out and leave colorless copper sulphate crystals.