Consider the following gaseous reversible reactions occuring in a closed vessel. Addition of argon gas at constant pressure favours forward reaction in the case of

Addition of inert gas at constant pressure favours reaction involving increase in number of moles; In option (4)   .   .   . nP>nR  ∴ forward reaction is favoured KC=PCl3Cl2PCl5;KC=nPCl3.nCl2nPCl5.V;Addition of inert gas increases ‘V’ thus denominator increases.To keep KC constant, numerator must increase.Products can increase only when PCl5 decomposes readily.