Pure PCl5 is introduced into an evacuated chamber and comes to equilibrium at 247oC and 2.0 atm. The equilibrium gaseous mixture contains 40% chlorine by volume. Calculate Kp at 247∘C for the reaction  PCl5(g)⇌PCl3(g)+Cl2(g)

The gaseous mixture contains 40% Cl2 and 40% PCl3,  since they are produced in 1 : 1 mole ratio. The PCl5% is 20 For ideal gases, mole % = volume%PCl2=PPCl3 PPCl3=nPCl3n×P=0.41×0.2= 0.80 atm PPCl5=2×0.2=0.40 atm Kp=PPCl3·PCl2PPCl5 =0.80×0.800.40=1.6 atm