Question

Match the following processes with entropy change:

Reaction		Entropy change
(i)	A liquid vapourises	(a)	$\Delta\,S=0$
(ii)	Reaction is non-spontaneouat all temperatures and $\Delta\,H$ is positives	(b)	$\Delta\,S$ = positive
(ii)i	Reversible expansion of an igasdeal	(c)	$\Delta\,S$ = negative

• A. $(i) \to (c) ; (ii) \to (b) ; (iii) \to (a)$
• B. $(i) \to (c) ; (ii) \to (a) ; (iii) \to (b)$
• C. $(i) \to (b) ; (ii) \to (c) ; (iii) \to (a)$
• D. $(i) \to (b) ; (ii) \to (a) ; (iii) \to (c)$

Answer 1

Answer: (C)

Reaction		Entropy change
i	A liquid vaporises	As a liquid change to gaseous state, the movement of molecules will increase and hence the entropy will also increase.
ii	Reaction is non-spontaneous at all temperatures and AH is positive.	$\Delta G$ is positive as the process in non-spontaneous. Also, $\Delta H$ is positive. Hence, $\Delta S$ is negative
iii	Reversible expansion of an ideal gas	This process at every stage is always in equal