For the reaction 4PH3(g)↽−−⇀6H2(g)+P4(g) 4 PH 3 ( g ) ↽ − − ⇀ 6 H 2 ( g ) + P 4 ( g )

Question

the equilibrium concentrations were found to be [PH3]=0.250 M,  [H2]=0.400 M, and [P4]=0.750 M.

What is the equilibrium constant for this reaction?

Answer 1

The equilibrium constant for the given balanced reaction is

K = [H2]⁶ [P4] / [PH3]⁴ where the products and reactant in brackets are their equilibrium concentrations.

K = 0.400⁶ x 0.750 / 0.250⁴ = 0.786