# Which of the following salts is not formed when $CuSO_4.5H_2O$ is heated ?

$\begin {array} {1 1} (A)\;CuSO_4.3H_2O & \quad (B)\;CuSO_4.2H_2O \\ (C)\;CuSO_4.H_2O & \quad (D)\;CuSO_4 \end {array}$

Answer : $CuSO_4.2H_2O$
$\quad \qquad \qquad (\text{exposure} ) \qquad \quad (373k) \quad \qquad \qquad (423 k)$
$CuSO_4.5H_2O \leftrightharpoons CuSO_4.3H_2O \leftrightharpoons CuSO_4.H_2O \leftrightharpoons CuSO_4$
$( \text{blue}) \qquad \qquad (\text{pale blue}) \qquad \quad \: \: ( \text{bluish white }) \qquad ( \text{white})$