Answer
a) $P-V$ diagram is shown in the figure.
b) $W = -6174.5\mathrm{J}$
Work Step by Step
a) Since the temperature is held constant, the $P-V$ diagram has the form $PV = \mathrm{constant}$.
b) In this problem, $P_2 = 3P_1$. This implies $V_2 = V_1/3$ since temperature is constant. For an isothermal process, the work done is given by
$W = nRT\ln\bigg(\frac{V_2}{V_1}\bigg)$
Here $n = 2$ and $T = 65^{\circ}\mathrm{C} =338\mathrm{K} $. Thus,
\begin{align}
W &= 2\times 8.314\times338\times\ln\bigg(\frac{V_1/3}{V_1}\bigg) \mathrm{J}\\
&=-2\times 8.314\times338\times\ln(3)\mathrm{J}\\
&=-6174.5\mathrm{J}
\end{align}
