JEE Main On 16 April 2018 Question 23

Question: The gas phase reaction $ 2NO _2(g)\to N _2O _4(g) $ is an exothermic reaction. The decomposition of $ N _2O _4, $ in equilibrium mixture of $ NO _2(g) $ and $ N _2O _4(g), $ can be increased by: [JEE Main 16-4-2018]

Options:

A) A increasing the pressure

B) addition of an inert gas at constant pressure

C) lowering the temperature

D) addition of an inert gas at constant volume

Show Answer

Answer:

Correct Answer: B

Solution:

  • reaction at equilibirium (1) according to Le chatelier’s principle- Increasing the pressure on a gas reaction shifts the position of equilibirium towards the side with fewer molecules. So, It will move in backward direction which leads to formation of $ N _2O _4 $ from $ NO _2. $ So option (1) is correct. (2)addition of an inert gas at constant pressure will increases volume and equilibirium shifts towards more number of molecules. (3) Decomposition of will be endothermic, so reaction will move in forward reaction when temperature is increased. So, It is incorrect. It will not effect reaction (volume is constant)