JEE · NEET Previous Year Question

In the following system,
at equilibrium, upon addition of xenon gas at constant , the concentration of

Topic: JEE PYQ

Answer: B. Full step-by-step solution below.

  1. A,& remain constant
  2. B will increase
  3. C will decrease
  4. D will increase

Correct answer: B

Solution

(b)
When xenon gas, an inert gas, is added to the equilibrium system
at a constant temperature and pressure, it affects the equilibrium according to Le Chatelier's principle. The addition of an inert gas at constant pressure effectively increases the volume of the system, reducing the concentration of the gases involved.
Since the system is at constant pressure, adding an inert gas increases the total volume, which favors the side of the reaction with more moles of gas. In this reaction, there are two moles of gas on the right side and ) compared to one mole on the left . Thus, the equilibrium will shift toward the right to increase the number of moles and counteract the change, decreasing the concentration of and increasing the concentrations of and .
However, due to the increase in overall volume, the individual concentrations of all species will decrease as a result of more space being available for the same amount of gas particles.

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