Question

The Kp for the production of phosgene is 18.0. If one mole each of CO and Cl2 are
mixed at the total pressure of 1 atm, what will be the partial pressure (in atm) of COCl2
after equilibrium is reached, CO(g) + Cl2(g)-->COCl2(g)

Answer 1

mols CO = 1
mols Cl2 = 1
total mols = 2
XCO = 1/2 = 0.5
XCl2 = 1/2 = 0.5
pCO = XCO * Ptotal = 0.5 x 1 = 0.5 atm
pCl2 = XCl2 * Ptotal = 0.5 x 1 = 0.5 atm

.......CO(g) + Cl2(g)-->COCl2(g)
I......0.5.....0.5........0
C.......-x......-x........x
E....0.5-x.....0.5-x......x

Substitute the E line into Kp expression and solve for x = pCOCl2