Thermodynamics and Thermochemistry - Result Question 29
####29. The direct conversion of $A$ to $B$ is difficult, hence it is carried out by the following shown path
Given that $\quad \Delta S _{(A \rightarrow C)}=50 eu$
$\Delta S _{(C \rightarrow D)}=30 eu$
$\Delta S _{(D \rightarrow B)}=-20$ 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,
$$ \begin{aligned} \Delta S _{A \rightarrow B} & =\Delta S _{A \rightarrow C}+\Delta S _{C \rightarrow D}+\Delta S _{D \rightarrow B} \ & =50 eu+30 eu+(-20 eu) \ & =60 eu \end{aligned} $$