Answer
$59^{\circ}C$
Work Step by Step
We find:
$\Delta S_{vap}=\frac{\Delta H_{vap}}{T_{b}}\implies T_{b}=\frac{\Delta H_{vap}}{\Delta S_{vap}}$
$=\frac{30.91\times10^{3}\,J/mol}{93.2\,J/K\cdot mol }=331.65\,K$
$=(331.65-273)^{\circ}C=59^{\circ}C$
