In which reaction there will be increase in entropy

In reaction (a) $\mathrm{Na}$ (s) reacts with ${\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$  to give $\mathrm{NaOH}\left(\mathrm{l}\right)$ and $\frac{1}{2}{\mathrm{H}}_2\left(\mathrm{g}\right)$

Since, the entropy of a gas is higher than  that of liquid and the entropy of liquid is higher than 
that of solid, therefore, the change in entropy of this reaction increases.