Question

Benzene and naphthalene from an ideal solution at room temperature. For this process, the true statement(s) is (are)

• A. $\Delta G$ is positive
• B. $\Delta S_{system}$ is positive
• C. $\Delta S_{surroundings}=0$
• D. $\Delta H=0$

Answer 1

Answer: (B), (C), (D)

$\Delta H=0$

When an ideal solution is formed process is spontaneous thus
According to Raoult’s law, for an ideal solution
$\Delta H=0,\Delta V_{min}=0$
From the relation
$\Delta G=\Delta H-T\Delta S$
$Since,\Delta H=0$
$\therefore \Delta G=-ve$
i.e. less than zero, and $\Delta S_{surroundings}=0$
Therefore, $\Delta S_{sys}=+ve$
i.e. more than zero.