Consider the reaction below.
at 500 k, the reaction is at equilibrium with the following concentrations.
[pci5]= 0.0095 m
[pci3] = 0.020
[ci2] = 0.020 m
what is the equilibrium constant for the given reaction?
0.042
0.42
2.4
24

Explanation:

Given decomposition reaction:

Equilibrium constant:

Stoichiometric coefficients and powers equal to 1 are not usually shown as they are understood, but I included them in order to shwow you how they intervene in the equilibrium expressions: each concentration is raised to a power equal to the respective stoichiometric coefficient in the equilibrium equation.

So, your calculations are: