The enthalpy of vaporization of water at ${100}^{\circ }\mathrm{C}$ is $40.63 \mathrm{kJ} {\mathrm{mol}}^{-1}$. Its entropy of vaporization would be

We know that entropy change in phase transformation is given as:

$$\begin{gathered} \mathrm{\Delta }S=\frac{\mathrm{\Delta }H}{T} \\ =\frac{40.63\times {10}^3\mathrm{J}{\mathrm{mol}}^{-1}}{373\mathrm{K}} \end{gathered}$$

So,

 $\mathrm{\Delta }S$$=108.9 \mathrm{J} {\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}$