Answer : The equilibrium concentrations of [tex]COCl_2,CO\text{ and }Cl_2[/tex] are, 0.2646, 0.0584 and 0.0584.
Explanation : Given,
Moles of  [tex]COCl_2[/tex] = 0.323 mole
Volume of solution = 1 L
Initial concentration of [tex]COCl_2[/tex] = 0.323 M
Let the moles of [tex]CO\text{ and }Cl_2[/tex] be, 'x'. So,
Concentration of [tex]CO[/tex] = x M
Concentration of [tex]Cl_2[/tex] = x M
The given balanced equilibrium reaction is,
               [tex]COCl_2(g)\rightleftharpoons CO(g)+Cl_2(g)[/tex]
Initial conc. Â Â Â Â Â 0.323 M Â Â Â Â Â 0 Â Â Â Â Â 0
At eqm. conc. Â Â (0.323-x) M Â Â (x M) Â Â Â (x M)
The expression for equilibrium constant for this reaction will be,
[tex]K_c=\frac{[CO][Cl_2]}{[COCl_2]}[/tex]
Now put all the given values in this expression, we get :
[tex]1.29\times 10^{-2}=\frac{(x)\times (x)}{(0.323-x)}[/tex]
By solving the term 'x', we get :
x = 0.0584
Thus, the concentrations of [tex]COCl_2,CO\text{ and }Cl_2[/tex] at equilibrium are :
Concentration of [tex]COCl_2[/tex] = (0.323-x) M Â = (0.323-0.0584) M = 0.2646 M
Concentration of [tex]CO[/tex] = x M = 0.0584 M
Concentration of [tex]Cl_2[/tex] = x M = 0.0584 M
Therefore, the equilibrium concentrations of [tex]COCl_2,CO\text{ and }Cl_2[/tex] are, 0.2646, 0.0584 and 0.0584.