Thermodynamics and Thermochemistry - Result Question 43

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

(2013 Adv.)

(a) $\Delta G$ is positive

(b) $\Delta S _{\text {system }}$ is positive

(c) $\Delta S _{\text {surroundings }}=0$

(d) $\Delta H=0$

Show Answer

Answer:

Correct Answer: 43. (b, c, d)

Solution:

PLAN: 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 $

$\therefore \quad \Delta G=-ve$

i.e. less than zero. and $\Delta S _{\text {surroundings }}=0$

Therefore, $\quad \Delta S _{\text {sys }}=+$ ve

i.e. more than zero.