Question

Assertion: At absolute zero temperature, vapour pressure, kinetic energy, and heat content of the gas reduce to zero.
Reason: At absolute zero, temperature velocity reduces to zero.
(A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
(B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
(C) Assertion is correct but Reason is incorrect.
(D) Assertion is correct but Reason is correct.

Answer 1

Hint : We know that to answer this question, you should recall the concept of properties of materials at absolute zero temperature. It is defined as the lowest possible temperature where nothing could be colder and no heat energy remains in a substance.

Complete Step By Step Answer:
We know that an ideal gas at constant pressure would reach zero volume at a temperature known as the absolute zero. Although, any real gas would condense to a liquid or a solid at a temperature higher than absolute zero; therefore, the ideal gas law is only an approximation to real gas behaviour. At this temperature the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. At absolute zero $\left( 0K \right)$ temperature, the thermal motion of gas molecules becomes negligible and hence their kinetic energy and vapour pressure also reduce to zero. We know that it is the theoretical point where all molecular motion ceases and they are at complete rest. Also as per kinetic theory, there should be no movement of individual molecules at absolute zero, so any material at this temperature would be solid.
Therefore the correct answer is option A, i.e. both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

Note :
Remember that at the higher temperature and lower pressure, a gas behaves like an ideal gas, as the potential energy due to intermolecular forces becomes less significant compared with the particle's kinetic energy, and the size of the molecules becomes less significant compared to the space between them.