13 Consider the following reaction at equilibrium 2NH3 g N2

13. Consider the following reaction at equilibrium 2NH3 (g) -N2 (g) 3H2 (g) Adding Na (g) to the system at equilibrium will a) decrease the concentration of NHs (g) at equilibrium b) decrease the concentration of H2 (g) at equilibrium c) increase the value of the equilibrium constant d) cause the reaction to shift to the right 14. In a reaction, A -.-> products, the initial concentration of A is 0.86 M and 40s later 0.78M. What is the initial rate of this reaction in M min? a) 1.2 x 10- b) 2.0 x 103 c) 2.2 x 102 d) 4.1 x 10-2

Solution

13. Ans:

b) option i.e decrease the concentration of H2 gas

# explanation:-

Effect of concentration on equilibrium:- According to Le-chatelier principle , if we will increase the concentration of reactants or decrease the concentration of products then equilibrium will shift in forward direction , and if we will decrease the concentration of reactants or increase the concentration of products then equilibrium will shifts in backward direction.

Therefore , on increasing the concentration of N2 gas , more amount of H2 reacts with N2 gas to give NH3 gas and hence concentration of H2 gas starts decreasing ( or conc. of NH3 starts increasing) and equilibrium shifts towards backward .

Note:- Equilibrium constant only changes with change in temperature .