Question

At room temperature $\left({27}^{\circ }C\right)$ the rms speed of the molecules of a certain diatomic gas is found to be $1920m/s$. The gas is

• A. $H_2$
• B. $F_2$
• C. $O_2$
• D. $C{l}_2$

Answer 1

The correct option is A $H_2$

Speed is supposed to be the $rms$ speed , given by $v=\sqrt[2]{2\frac{3RT}{M}}$, Where $R$ is gas constant.

Given that $T=27+273=300Kelvin$, $R=8.31J/Kelvin$ and $v=1920m/s$ putting all these to the expression,

we get $M=.02$ i.e. Molar weight is $.02gm/mole$