Van der Waals equation for water is given by

\[p=\frac{0.004619 T}{v-0.0016891}-\frac{0.017034}{v^{2}}\]

where \(p=\) pressure (bar), \(v=\) specific volume \(\left(\mathrm{m}^{3} / \mathrm{kmol}\right), T=\) temperature (K).

Draw a \(p-v\) diagram for the following isotherms: \(250{ }^{\circ} \mathrm{C}, 270{ }^{\circ} \mathrm{C}, 300{ }^{\circ} \mathrm{C}, 330{ }^{\circ} \mathrm{C}, 374{ }^{\circ} \mathrm{C}\), \(390^{\circ} \mathrm{C}\).

Compare the computed specific volumes with Steam Table values and explain the differences in terms of the value of \(p_{\mathrm{c}} v_{\mathrm{c}} / \Re T_{\mathrm{c}}\).