Question

At room temperature, the rms speed of the molecules of a certain diatomic gas is found to be 1920ms^-1. Which is the gas?

(a) H2

(b) F2

(c) O2

(d) Cl2

I got this question in an interview for internship.

Question is from Ideal Gases topic in section Kinetic Theory of Gases of Engineering Physics I

Answer 1

Right option is (a) H2

The best explanation: vrms=√(3RT/M)

M=3RT/(vrms)^2 = (3×8.3×300)/(1920)^2 = 2

Hence the gas is H2.