Question

the degree of dissociation is 0.4 at 400k and 1 atm for the gaseous

Answer 1

                     PCl5↔  PCl3 +Cl2Initial moles     1         0           0Moles at equil: 1−0.4  0.4      0.4Total moles at equilibrium =1 −0.4+0.4+0.4 =1.4AlsoNormal wt of PCl5/ Exp.m wt.of PCl5 = 1+α =1.4208.5/exp.m. wt  = 1.4Exp.m. wt = 208.5/1.4Again PV =wMRT    d = wV= PmRT=1×208.51.4×0.082××400= 4.53g/L