Write a relation between `DeltaG` and Q and deifine the meaning of each term and answer the following :
Why a reaction proceeds forward when `QltK` and no net reaction occure when `Q=K`.
Explain the effect of increase in presure in terms of reaction quotient Q for the reaction : `CO(g)+3H_2(g)hArrCH_4(g)+H_2O(g)`

Explanation

Relation between `DeltaG` and Q may be written as :
`DeltaG=DeltaG^(Theta)+RT` in Q
Here `DeltaG^(Theta)=` change in free energy as the reaction proceeds.
`DeltaG^(Theta)=` standard free energy change.
Q=Reaction quotient.
R= Gas constant.
T=Absolute temperature.
We know that `DeltaG(Theta)=-RT` in K.
therefore` DeltaG=-RT " In "K+RT" In "Q=RT" In "(Q)/(K)`
(a) If `Q lt K` then `DeltaG` is negative-Reaction proceeds in the forward dirction.
If Q=K, `DeltaG=0`. No net reaction occurs under the reaction conditions.
(b) The given reaction is:
`CO(g)+3H_2(g)hArrCH_4(g)+H_2(g)`
`Q_(p)=([CH_4(g)][H_2(g)])/([CO(g)][H_2(g)]^(3)]`
Since the number of product moles is less than the number of reactant moles, `Q lt K`. Therefore, the reaction proceeds in the forward dirction.