Q.
Calculate the percent dissociation of H2S(g) if 0.1mole of H2S is kept in 0.4 litre vessel at 1000K.
For the reaction : 2H2S(g)⇌2H2(g)+S2(g)
the value of KC is 1.0×10−6.
Molar conc. of H2S=0.40.1molL−1=0.25molL−1
Suppose degree of dissociation of H2S=α then 2H2S⇌2H2+S2 0.25M 0.25(1−α),0.25α,20.25α =0.125α=0.125α KC=[H2S]2[H2]2[S2] 10−6=[0.25(1−2)]2(0.25α)2(0.125α)
Neglecting in comparison to 1 we get 10−6=(0.25)2(0.25α)2(0.125α)=0.02 % age dissociation =0.02×100=2%