Question

Calculate the degree of dissociation of pcl5 if the vapour density at the given temperature is 70.

Answer 1

Initial vapour density/vapour density at equilibrium=mole at equilibrium/mole initial

PCL5 -----PCL3 +CL2

let the initial concentration be C

concentration of PCL3=C-Cx,x is the degree of dissociation

PCL3=Cx

CL2=Cx

total mole at equilibrium=C +Cx

initial mole=C

therefore

C +Cx/C =104.25/70

1+x=1.485

x=.485

i hope it helped u

Answer 2

Initial vapour density at equilibrium=mole at equilibrium

PCl5 -----> PCl3 +Cl2

Let the initial concentration be C

Concentration of PCl5=C-Cx, where x is the degree of dissociation

PCl3=Cx

Cl2=Cx

Therefore, total mole at equilibrium=C +Cx

initial mole=C

According to question,

C +Cx/C =104.25/70

=>1+x=1.485

=>x=.485 {ANS}