First step is to find the concentrations of the substances in the flask. The concentrations of Cl2, NOCl, and NO are 0.8 mol/L, 0.33 mol/L , and 0.0045 mol/L. Then calculate the solubility constant using this formula,
[0.8][0.0015]²/[0.033]². The result is 1.7*10^(-5).