Are van der Waals coefficients independent of temperature?
The van der waals constant can be directly obtained from the critical temperature and pressure. We have,

${a = \frac{27 R^2 T_c^2}  {64 P_c}}$
${b =  \frac{R T_c }{ 8 P_c}}$

Since, $T_c$ and $P_c$ are constants, we can conclude that the van der waals constants are really &quot;constants.&quot;