The equilibrium constant for the reaction 2 Fe3aq Hg22aq 2

The equilibrium constant for the reaction,

2 Fe³⁺(aq) + Hg₂²⁺(aq) <=> 2 Fe²⁺(aq) + 2 Hg²⁺(aq)
is 9.1 x 10^-6(aq) at 298 K. Calculate ?G in kJ when

[Fe³⁺(aq)] = 0.783
[Hg₂²⁺(aq)] = 0.0128
[Fe²⁺(aq)] = 0.0497
[Hg²⁺(aq)] = 0.0827

Solution

Q = [Fe2+]^2*[Hg2+]^2/[Fe3+]^2*[Hg22+]

= 2.1527 * 10^-3

Delta G = -RTln(K/Q) =13.543 KJ