At certain temperature, a compound AB2 dissociates as: 2AB2(g)→2AB(g)+B2(g) with a degree of dissociation α, which is very small compared to unity. The expression of Kp in terms of α and total pressure P is ?
α3P2
2AB2→2AB+B2
1−α α α2
Total moles =1−α+α+α2=2+α2
PAB2=(1−α)P(2+α)2=2(1−α)P(2+α):PAB=αP(2+α)2=2αP2+α;PB2=α2P(2+α)2=αP2+αHence,KP=P2ABPB2P2AB2=(2αP2+α)2[2(1−α)P2+α]2
=α3P2 (α<<1)