d
\((R \cdot M . s) \text { velocity }=\sqrt{\frac{3 R T}{M}}\)

Here, \(M\) is the molecular mass.

\(\text { Mow, No- of moles, } n=\frac{\text { mass }}{\text { Molecular mass }}=\frac{m}{M}\)

\(\therefore(R \cdot M \cdot S)=\sqrt{\frac{3 R T n}{m}}\)

\(\therefore(R M S) \propto \frac{1}{\sqrt{m}}\)