Question

The direct conversion of $A$ to $B$ is difficult, hence it is carried out by the following shown path

Given that $\Delta S_{(A \rightarrow C)}=50$ eu
$\Delta S_{(C \rightarrow D)}=30$ eu
$\Delta S_{(D \rightarrow B)}=-20$ eu
where, eu is entropy unit
Then, $\Delta S_{(A \rightarrow B)}$ is

• A. + 100 eu
• B. + 60eu
• C. -100 eu
• D. -60 eu

Answer 1

Answer: (B)

Entropy is a state function hence.
$ \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 $