Suppose 4.2 mol of oxygen and 4.0 mol of no are introduced to an evacuated 0.50-l reaction vessel. at a specific temperature, the equilibrium 2no(g) + o2(g) picture 2no2(g) is reached when [no] = 1.6 m. calculate kc for the reaction at this temperature.

Answer : The value of for the reaction is, 3.9

Solution :  Given,

Moles of = 4.2 mol

Moles of = 4.0 mol

First we have to calculate the concentration of .

Now we have to calculate the value of equilibrium constant.

The given equilibrium reaction is,

Initially conc.       8.4       8.0          0

At eqm.             (8.4-2x)  (8.0-x)     2x

The expression of will be,

      .......(1)

The concentration of NO at equilibrium = 1.6 M = (8.4-2x)

So,

8.4 - 2x = 1.6

x = 3.4

Now put the value of 'x' in the above equation 1, we get:

Therefore, the value of for the reaction is, 3.9