Question

On heating, hydrated copper sulphate changes its colour from ___________ to ________________.

• A. blue
• B. white

Answer 1

• The molecular formula of hydrated Copper sulphate (${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$) is blue in colour.
• When it is heated water molecule remove from it and called anhydrous copper sulphate which is white in colour.
• $$\begin{gathered} {\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}\left(\mathrm{s}\right)\stackrel{∆}{\to }{\mathrm{CuSO}}_4\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right) \\ \mathrm{Hydrated}\mathrm{copper}\mathrm{sulphate}\mathrm{Anhydrous}\mathrm{copper}\mathrm{sulphate}\mathrm{water} \end{gathered}$$

Therefore, on heating hydrated copper sulphate changes its colour from blue to white.