Question

Which of the following gas has the largest value of Van Der Waals constant.
(1). $C{O_2}$
(2). $N{O_2}$
(3). ${H_2}$
(4). $N{H_3}$

Answer 1

Hint: Due to faulty postulates of Kinetic Theory of Gases, the concept of ideal gas came into account. However, it was found that no gas generally behaves ideally. In fact, the gases behave as real gases. The concept of real gas was proposed after the experimental failure of the ideal gas equation, but however, gas laws were obeyed at different conditions.

Complete answer:
The Kinetic Theory of Gases was put forward by Maxwell and Boltzmann. However, out of seven postulates, two postulates were found to be faulty. These two postulates were not correct in order to understand the gaseous states of matter. These two faulty postulates were: - (i) the point mass of gas and negligible volume and (ii) there are no intermolecular forces between the particles.
These faulty arguments lead to the ideal gas equation $PV = nRT$ , but this equation was not obeyed by all the gases at all the time. It was Van Der Wall’s work that detects the faults and gives corrections to the faulty assumptions. He put forward two constants, $a$ , and $b$ . The constant $b$ was for the volume correction and the constant $a$ is for the intermolecular force of attraction’s correction.
However, ${H_2}$ is still an exception to Van Der Waals corrections. Out of all the gases mentioned above $N{H_3}$ has the largest value of Van Der Waals constant, due to its small size and hydrogen bonds present in it.

So, the correct answer is “Option A”.

Note:
It is to remember that, not all the time the assumptions put forward by the great scientists are always correct and accurate. The classical example of such a mistake is the Kinetic Theory of Gases also called K.T.G. $N{H_3}$ has the largest value of Van Der Waals constant, due to its small size and hydrogen bonds present in it.