The equilibrium constant kc for the decomposition of phosgene, cocl2, is 4.63 10-3 at 527°c. cocl2(g) equilibrium reaction arrow co(g) + cl2(g) calculate the equilibrium partial pressure of all the components, starting with pure phosgene at 0.760 atm.

By using Kp formula:
Kp = Kc RTΔn
when Kc = 4.63x10^-3 
R = 0.0821
T= 527 + 273 = 800 K
Δn = moles of products - moles of reactants = 2-1 = 1 
by substitution:
Kp= 4.63x10^-3 * 0.0821 * 800 = 0.304 
from ICE table:
             COCl2(g) → CO(g) +Cl2(g)
initial      0.760             0         0
change  -X                 +X         +X
final       (0.760-X)        +X        +X
by substitution:
Kp = P(CO)*P(Cl2) / p(COCl2) 
4.63x10^-3 = X*X / (0.76- X)
∴X = 0.057 
∴P(CO) = 0.057
  P(Cl2) = 0.057 atm
 and P(COCl2) = 0.760-0.057 = 0.703 atm   

The correct answer is d