initial vapour densuty/vapour density at equilibrium=mole at equilibrium/mole initialPCL5 -----PCL3 +CL2let the initial concentration be Cconcentration of PCL3=C-Cx,x is the degree of dissociationPCL3=CxCL2=Cxtotal mole at equilibrium=C +Cxinitial mole=CthereforeC +Cx/C =104.25/701+x=1.485x=.485