The heat of solution of anhydrous CuSO_4 and CuSO_4 · 5 H_2 O are -70 ~kJ ~mol^-1 and +12 ~kJ ~mol^-1 respectively. The heat of hydration of CuSO_4 to CuSO_4 · 5 H_2 O is -x ~kJ . The value of x is ______ (nearest integer).

Correct answer: 82. from (1) \ (2) -70=x+12 x=-82

Q30 / 90 · JEE Main 2024 (09 Apr Shift 1) · Chemistry

The heat of solution of anhydrous $\mathrm{CuSO}_4$ and $\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}$ are $-70 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $+12 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. The heat of hydration of $\mathrm{CuSO}_4$ to $\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}$ is $-x \mathrm{~kJ}$. The value of $x$ is ______ (nearest integer).

Correct answer: 82

$\begin{gathered}\text { from }(1) \&(2) \\ -70=x+12 \\ x=-82\end{gathered}$

Hence, the correct answer is 82.