The maximum number of molecules is present in

$\begin{array}{l}\mathrm{Moles}\mathrm{of}{\mathrm{H}}_2=\frac{15}{22.4}=0.67\\ \mathrm{Moles}\mathrm{of}{\mathrm{N}}_2=\frac{5}{22.4}=0.22\end{array}$

$\begin{array}{l}\mathrm{Moles}\mathrm{of}{\mathrm{H}}_2=\frac{0.5}{2}=0.25\\ \mathrm{Moles}\mathrm{of}{\mathrm{O}}_2=\frac{10}{32}=0.31\end{array}$

larger is the number of mole, the more is the number of molecule.