Three gases A,B and C are at same temperture if their r.m.s speed are in the ratio 1:`1/sqrt2:1/sqrt3` then their molar masses will be in the ratio :

Options

A. `1:2:3`
B. `3:2:1`
C. `1:sqrt2:sqrt3`
D. `sqrt3:sqrt2:1`

Answer

A

Explanation

`V_("rms")^2=(3RT)/(M)`
`V_A:V_B:V_C=1:1//sqrt2:1//sqrt3`
`V_A^2:V_B^2:V_C^2=1:1//2:1//3`
`1/M_A:1/M_B:1/M_C=1:1/2:1/3`
`M_A:M_B:M_C=1:2:3`