An equilibrium constant can be used to calculate the composition of an equilibrium mixture.
Consider an equilibrium reaction, A(aq) + B(aq) ⇌ C(aq) + D(aq)
The equilibrium constant is 4.0 at a certain temperature.
Let the initial amount of A and B be 2.0 mol in ‘V’ litres. Let x mol be the equilibrium amount of C.
Hence, we can construct a table as shown below:
The expression for equilibrium constant can be written as:
Substituting the value of equilibrium concentration, we get
Therefore, equilibrium concentrations are 0.67 mol of A, 0.67 mol of B, 1.33 mol of C and 1.33 mol of D in V litres.
