Question

The ratio of the vapour densities of two gases at a given temperature is 9:8. The ratio of the rms velocities of their molecules is ___________

(a) 3:2√2

(b) 2√2:3

(c) 9:8

(d) 8:9

This question was addressed to me during an online exam.

This is a very interesting question from Gases and Reactions topic in portion Kinetic Theory of Gases of Engineering Physics I

Answer 1

Correct choice is (b) 2√2:3

Easy explanation: At a given temperature,

(vrms (1))/(vrms (2))=√(8/9)=2√2:3.