Question:
Consider a mixture of gas molecule of types $A, B$ and $\mathrm{C}$ having masses $\mathrm{m}_{\mathrm{A}}<\mathrm{m}_{\mathrm{B}}<\mathrm{m}_{\mathrm{C}}$. The ratio of their root mean square speeds at normal temperature and pressure is :
Correct Option: , 4
Solution:
$\mathrm{V}_{\mathrm{RMS}}=\sqrt{\frac{3 \mathrm{RT}}{\mathrm{M}}}$
$m_{\mathrm{A}}<\mathrm{m}_{\mathrm{B}}<\mathrm{m}_{\mathrm{C}}$
$\Rightarrow \mathrm{V}_{\mathrm{A}}>\mathrm{V}_{\mathrm{B}}>\mathrm{V}_{\mathrm{C}}$
$\Rightarrow \frac{1}{\mathrm{~V}_{\mathrm{A}}}<\frac{1}{\mathrm{~V}_{\mathrm{B}}}<\frac{1}{\mathrm{~V}_{\mathrm{C}}}$