Question

The equilibrium constant for the reaction SO2(g)+NO2(g)⇌SO3(g)+NO(g) is 2.9.

Find the amount of NO2 that must be added to 2.2 mol of SO2 in order to form 1.2 mol of SO3 at equilibrium.

Answer 1

                 SO2 (g) + NO2 (g) ⇌ SO3 (g) + NO (g)

initial        x                  y                 0               0

at equ    (x - z)          (y - z)            z     z

given z = 1.3

K = [NO] [SO3] / [SO2] [NO2]

2.9 = (1.3) (1.3) / (x - 1.3) (y - 1.3)

and x = 2.2 then

2.9 = (1.3) (1.3) / ((2.2 - 1.3) (y - 1.3))

y = 1.947 mol