Question

the reaction for the decomposition of hydrogen disulfide:

2H2S(g)⇌2H2(g)+S2(g), Kc=1.67×10−7 at 800 ∘C

The reaction is carried out at the same temperature with the following initial concentrations:

[H2S]=1.90×10−4 M

[H2]= 0M

[S2]= 0M

Find the equilibrium concentration of S2

Answer 1

2H2S(g)   <--------------->2H2(g) +    S2(g),

1.90x 10^-4                       0                  0

1.90x 10^-4 - 2x                2x                 x

Kc = [H2]^2[S2] / [H2S]^2

1.67×10^−7 = (2x)^2 x / (1.90x 10^-4 - 2x)^2

x = 1.06 x 10^-5

equilibrium concentration of [S2] = 1.06 x 10^-5 M