Let us assume that initially, 100 moles of SO2Cl2 are present.
91.2 moles of SO2Cl2 decompose to form 91.2 moles of SO2 and 91.2 moles of Cl2.
100−91.2=8.8 moles of SO2Cl2 remains.
The mole fraction of SO2Cl2 at equilibrium =8.8100=0.088
The partial pressure of SO2Cl2 at equilibrium =0.088×1atm=0.088atm.
The mole fraction of SO2 at equilibrium =91.2100=0.912
The partial pressure of SO2 at equilibrium =0.912×1atm=0.912atm.
The mole fraction of Cl2 at equilibrium =91.2100=0.912
The partial pressure of Cl2 at equilibrium =0.912×1atm=0.912atm.
KP=PSO2PCl2PSO2Cl2
KP=0.912atm×0.912atm0.088atm
KP=9.45atm