construct the ICE table
              Â
CH4(g)Â Â Â + 2
H2S(g)     ↔
CS2(g)Â Â Â +Â Â Â Â 4
H2(g)
IÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0.2Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0.6Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0.2Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0.6
CÂ Â Â Â Â Â Â Â Â Â Â Â Â Â
-x                   Â
-2x                   Â
+x                  Â
+4x
EÂ Â Â Â Â Â Â Â Â Â Â Â Â
0.2-x               Â
0.6-2x              Â
0.2+x              Â
0.6+4x
he has given equilibrium concentration of CH4
= [CH4] = 0.15Â Â
but from ICE table equilibrium concentration of CH4 = 0.2-x
0.2-x = 0.15
x = 0.2 - 0.15 = 0.05M
now equilibrium concentratiof H2 from ICE table
[H2] = 0.6 + 4x
put the above obtained x value here
= 0.6 + 4 (0.05)
= 0.6 + 0.2
[H2] at equilibrium= 0.8M
