For the complex formation reaction where M is any metal and L is any ligand, M++
ID: 1001132 • Letter: F
Question
For the complex formation reaction where M is any metal and L is any ligand, M++2L[ML2]+ Kf is the formation constant for the complex at equilibrium and G is the Gibbs free energy change for the reaction at equilibrium.The formation constant (Kf) can be related to the Gibbs free energy change (G) for a reaction by the equation G=RTln Kf where T is the temperature in kelvins and R is the gas constant equal to 8.314 JK1mol1. The complex formation is generally a spontaneous process; thus, the Gibbs free energy change is negative. Calculate the formation constant for the formation of [Ni(NH3)4(H2O)2]2+ from [Ni(H2O)6]2+, given that G is 46.3kJmol1 at 298 K. Express your answer numerically to three significant figures.
Explanation / Answer
G=RTln Kf
ln Kf = - G/RT
R = 8.314 JK1mol1
T = 298 K
G is 46.3kJmol1 = -46300 J mol-1
ln Kf = - (-46300)/[(8.314)(298)]
ln Kf= 18.7
Kf = 1.31 *108
Formation constant = 1.31 *108