The root mean square speeds at STP for the gases `H_(2^+), N_(2^+),O_2` and HBr are in the order :

Options

A. `H_2 lt N_2 lt O_2 lt HBr`
B. `HBr gt O_2 gt N_2 gt H_2`
C. `H_2 gt N_2 = O_2 gt HBr`
D. `HBr lt O_2 lt H_2 gt N_2`

Answer

B

Explanation

`V_(rms) = sqrt((3RT)/(M))`
(T will same at STP)
`V_(rms) prop 1/(sqrt(M))`
`therefore v_(rms) HBr lt O_2 lt N_2 lt H_2`