Dihydrogen gas is obtained from natural gas by partial oxidation with steam as per following endothermic reaction:
`CH_(4)(g)+H_(2)O(g) hArr CO(g)+3H_(2)(g)`
a. Write an expression for K_(p) for the above reaction.
b. How will the value of K_(p) and composition of equilibrium mixture be affected by
i. Increasing the pressure
ii. Increasing the temperature
iii. Using a catalyst?

Explanation

The expression for `K_(p)` for the reaction is :
`K_(p) ((pCO) xx (pH_(2))^(3))/((pCH_(4))xx(pH_(2)O))`
(I) By increasing the pressure ,the no. of moles per unit volume will increase. In order to decrease the same , the equilibrium gets shifted to the left or in the backward direction. As a result , more or reactants will be formed and the value of `K_(p)` will decrease.
(ii) If the temperature is increased according to Le Chatelier's principle ,the forward reaction will be favoured as it is endothermic. Therefore. the equilibrium gets shifted to the right and the value of `K_(p)` will increase.
(iii) The addition of catalyst will not change the equilibrium since it influences both the forward and the backward reactions to the same extent. But it will be attained more quickly.