Question

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

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

Answer 1

Answer: (D)

$?H = 0$

Answer 2

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