In the reversible reaction A + B ⇌ C + D, the concentration of each C and D at
equilibrium was 0.8 mole/litre, then the equilibrium constant KC will be
16.0
Suppose 1 mole of A and B each taken then 0.8 mole/litre of C and D each
formed remaining concentration of A and B will be (1 − 0.8) = 0.2 mole/litre
each.
Equilibrium constant = [C][D][A][B] = 0.8 × 0.80.2 × 0.2 = 16