[QUE/TH-08008] TH-PROBLEM

For a system, as in $Q[2]$, undergoing a process from state 1
to state 2 at constant pressure and temperature, show that the
maximum ``non'' $PdV$ work out put is given by
\begin{eqnarray}
|A_{TP}| \le G_1-G_2 &\qquad G=\text{Gibbs function}&
\end{eqnarray}