Write the relation between Delta G^(@) and equilibrium constant.

1.	Write the relation between Delta G^(@) and equilibrium constant.
Answer» `Delta G^(@) = -2.303 RT LOG K` ` Delta G^(@) = - RT log K` ` Delta G^(@) = 2.303 RT log K` ` Delta G^(@) = -2.303 log K` Solution :Consider a reversible reaction, `A + B hArr C + D`. The RELATIONSHIP between Gibb's free ENERGY change `(Delta G)` at any TIME and standard Gibb's free energy change `(Delta G^(@))` of the reaction is `Delta G = Delta G^(@) + RT ln Q` where `Q = (p_(C ).p_(D))/(p_(A).p_(B))` at any given time. This equation is called "Van't Hoff's reaction isotherm.". When the reaction attains equilibrium, `Delta G = 0` and `(p_(C ).p_(D))/(p_(A).p_(B)) = K`. The above equation becomes, `0 = Delta G^(@) + RT ln K` or `Delta G^(@) = -RT ln K` `:. Delta G^(@) = -2.303 RT log K` `Delta G^(@)` is the standard free energy change of the reaction, R is the gas constant, T is the temperature in absolute scale and `K_(p)` is the equilibrium constant In general, for `aA + bB hArr c C + d D` `Delta G^(@) = -2.303 RT log K_(p)` where `K_(p) = (p_(C ).p_(D))/(p_(A).p_(B))`

Discussion