Question

A mixture of gases is at equilibrium:

4 NO (g) → 2 N2O (g) + O2 (g) ∆H = -199.5 kJ

(a) Does the equilibrium shift to the left or to the right when some O2 (g) is removed from the reaction mixture?

(b) Does the equilibrium shift to the left or to the right when some NO (g) is added to the reaction mixture?

c) In which direction does the equilibrium shift as the temperature is lowered?

(d) In which direction does the equilibrium shift as pressure is applied to the system?

Answer 1

a) When O_{​​​​​​2} is removed, the product concentration decreases and according to Le Chatelier principle, reaction move in direction to increase product concentration . So the equilibrium shift to right .

b) When NO is added to the mixture, we increase the concentration of reactants but according to Le Chatelier principle the reaction move in direction to decrease the concentration of NO .Hence reaction will shift to the right .

c) The reaction is exothermic i.e.heat energy is released , so when we lowered the temperature the reaction will move in direction so that temperature can be increased .Thus the reaction shift towards right so that more heat can be evolved.

d) When pressure is applied to the system ,the pressure is increased more on reactants side due to greater number of moles .Reaction ,thus according to Le Chatelier principle move in direction to decrease the pressure on reactants side i.e.it moves to the direction where there is less no.of moles .It will shift to right.