Question

What is the ratio of the velocities of 2 moles of hydrogen to five moles of helium?

(a) \(\sqrt{14}\)

(b) \(\sqrt{10}\)

(c) \(\sqrt{20}\)

(d) \(\sqrt{50}\)

The question was posed to me by my school teacher while I was bunking the class.

This key question is from States of Matter topic in chapter States of Matter of Chemistry – Class 11

Answer 1

The correct choice is (b) \(\sqrt{10}\)

Best explanation: The formula of average speed is given by \(\sqrt{2RT/M}\). We know that the velocity of gas molecules is inversely proportional to the root over the mass of the gas. So here the ratio of velocities is \(\sqrt{5×4/2×1}\) = \(\sqrt{10}\).