Determine the equilibrium constant Kc for the reaction PbBr2

Determine the equilibrium constant, Kc, for the reaction: PbBr2(s) + 2 OH–(aq) Pb(OH)2(s) + 2 Br–(aq)

Given the following equilibria,

PbBr2(s) --> Pb2+(aq) + 2 Br–(aq)

Pb(OH)2(s -->) Pb2+(aq) + 2 OH–(aq)

K1 = 6.6 x 10–6

K2 = 1.4 x 10–15

Answer is 4.7E9 - i just need the steps - thanks!

Solution

Reversing equation two and then adding the equations give the desired equation

Hence

K(final) = K1/K2 = 6.6 * 10^-6 / 1.4 * 10^-15

Solving

K(Final) = 4.714 * 10^9