Question

If a reaction mixture initially contains 0.195 m so2cl2, what is the equilibrium concentration of cl2 at 227 ???c?

Answer 1

Missing in your question the K constant value =2.99X10^-7
The reaction equation:
         SOCl2 ⇄ SO2 +Cl2
initial 0.195          0        0
         -X             +X      +X
final  (0.195-X)      X        X

K= [SO2][Cl2]/SOCl2
by substitution
2.99X10^-7 = (X)(X)/(0.195-X)
2.99X10^-7 = X^2 / (0.195-X) by solving this equation 
∴X = 0.00024 = 2.4 X10^-4 
∴[Cl2] = 2.4X10^-4 m