The total number of gram-molecules of ${\mathrm{SO}}_2{\mathrm{Cl}}_2$ in 13.5 g of sulphuryl chloride is

 Molecular weight of ${\mathrm{SO}}_2{\mathrm{Cl}}_2$  = 32 + 32 + 2 x 35.5 = 135 g

$\begin{array}{l}\because 135\mathrm{g}\mathrm{of}{\mathrm{SO}}_2{\mathrm{Cl}}_2=1\mathrm{gm}\mathrm{molecule}\\ \therefore 13.5\mathrm{g}\mathrm{of}{\mathrm{SO}}_2{\mathrm{Cl}}_2=\frac{1}{135}\times 13.5=0.1\end{array}$