The gas having average speed four times as that of `SO_(2)` (molecular mass 64) is

Options

A. He (molecular mass 4)
B. `O_(2)` (molecular mass 32)
C. `H_(2)` (molecular mass 2)
D. `CH_(4)` (molecular mass 16)

Answer

A

Explanation

Average speed `(v_("av"))` of gas molecules is inversely proportional to the square root of the absolute temperature (T) of the gas. `v_(av)=sqrt((8RT)/(piM))`
When R is gas constant and M the molecular weight.
Given, `v_(1)=v, M_(1)=64, v_(2)=4v`
`(v)/(4v)=sqrt((M_(2))/(64))`
`Rightarrow M_(2)=(64)/(16)=4`
Hence, the gas is helium (molecular mass 4).