54. Write a relation between G and Q and define the meaning of each term and answer the following.

(a) Why a reaction proceeds forward when Q

(b) Explain the effect of increase in pressure in terms of reaction quotient Q. For the reaction, CO(g)+3H2(g)CH4(g)+H2O(g)

The relation between G and Q is
G=G+RTlnQG=change in free energy as the reaction proceeds.G=standard free energyQ=reaction quotientR=gas constantT=absolute temperature in K
(a) G=-RT ln K
G=-RT ln K+RT ln QG=RT ln QK
If Q < K, G will be negative and the reaction proceeds in the forward reaction.
If Q = K, G=0 reaction is in equilibrium and there is no net reaction.
(b) CO(g)+3H2(g)CH4(g)+H2O(g)
Kc=[CH4][H2O][CO][H2]3
On increasing pressure, volume decreases. If we doubled the pressure, volume will be halved but the molar concentrations will be doubled. Then,
Qc=2[CH4]·2[H2O]2[CO]{2[H2]}3=14[CH4][H2O][CO][H2]3=14Kc
Therefore, Qc is less than Kc, so Qc will tend to increase to re-establish equilibrium and the reaction will go in forward direction.