The dissociation of phosgene gas `(COCl_(2))` is represented as :
`COCl_(2) (g) hArr CO(g) + Cl_(2)(g)`
When the mixture of these three gases is compressed at constanat temperature , what happens to (i) the amount of CO in the mixture (ii) the partial pressure of `COCl_(2)` (iii) the equilibrium constant for the reaction ?

Explanation

The dissociation reaction proceeds with the increase in the number of moles per unit volume . When the mixture of the gases is compressed at constant temperature, this means that the number of moles per unit volume further increase . In order to undo the effect, the equilibrium must shift to the left As a result,
`COCl_(2)(g)hArr CO(g) +Cl_(2)(g)`
(i) the amount of `CO(g)` in the mixture decreases.
(ii) The partial pressure of `COCl_(2)(g)` increase.
(iii) Since the partial pressure of both CO(g) and `Cl_(2)(g)` decrease and that of `COCl_(2)(g)` increases, therefore the value of `K_(p)` decreases.