Thermodynamics and Thermochemistry 1 Question 26
29. The direct conversion of $A$ to $B$ is difficult, hence it is carried out by the following shown path
Given that $\quad \Delta S_{(A \rightarrow C)}=50 \mathrm{eu}$
$\Delta S_{(C \rightarrow D)}=30 \mathrm{eu}$
$\Delta S_{(D \rightarrow B)}=-20$ euwhere, eu is entropy unit
Then, $\Delta S_{(A \rightarrow B)}$ is
(2006, 3M)
(a) +100 eu
(b) +60 eu
(c) -100 eu
(d) -60 eu
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Solution:
- Entropy is a state function hence,
$$ \begin{aligned} \Delta S_{A \rightarrow B} & =\Delta S_{A \rightarrow C}+\Delta S_{C \rightarrow D}+\Delta S_{D \rightarrow B} \ & =50 \mathrm{eu}+30 \mathrm{eu}+(-20 \mathrm{eu}) \ & =60 \mathrm{eu} \end{aligned} $$
