Statement I: The total kinetic energy of vapours formed over liquid water in closed container A and B having free space 1 l and 2 l, respectively, over water at the same temperature is in the ratio 1:

Question

Statement I: The total kinetic energy of vapours formed over liquid water in closed container A and B having free space 1 l and 2 l, respectively, over water at the same temperature is in the ratio 1:2, assuming ideal behaviour of vapours. Statement II: Vapour pressure of a pure substance depends only on temperature.

Prashant Kotian · Accepted Answer

Correct answer: A. Since the temperature is the same, the vapour pressure of water is identical in both containers. The volume of the vapour phase in B (2 L) is twice that in A (1 L), so container B contains twice as many moles of water vapour as A. Because kinetic energy is ∝ the number of moles (K.E. = 1.5 nRT), the K.E. ratio is indeed 1:2. This is directly explained by the constant vapour pressure (Statement II).

💡 Solution & Explanation

Practice 22,000+ questions like this