Question

Two moles of NH₃ are introduced into the one-litre flask in which it dissociates at high temperature as follows: 2NH₃(g)  ⇌ N₂(g) + 3H₂(g). Determine Kc, if at equilibrium 1 mole of NH₃ remains.

Answer 1

                             2NH₃        ⇌       N₂       +      3H₂

Initial conc.          2 mol L^-1             0                 0

At equilibrium     1  mol L^-1       0.5 mol L^-1        1.5 mol L^-1

Now.               `K_c = ([N_2][H_2]^3)/([NH_3]^2) = ([0.5][1.5]^2)/([1.0]^2)`

                       `K_c = 1.6875 " mol"^2 L^-2`