At certain temperature, kc for the reaction, PCl5 > PCl3 + Cl2, is equal to 3.33. After .20 mole of PCL5 and 1.0 mole of PCL3 are introduced iinto a 2.00 L evacuated chamber, calculate the equilibrium concentration of PCl5.

Answer : The equilibrium concentration of is, 0.16 M

Explanation :

First we have to calculate the concentration of

and,

The given chemical reaction is:

Initial conc.      0.4           2.0          0

At eqm.          (0.4-x)      (2.0+x)       x

The expression for equilibrium constant is:

Now put all the given values in this expression, we get:

x = -5.57 and x = 0.24

We are neglecting the value of x = -5.57 because equilibrium concentration can not be more than initial concentration.

Thus, the value of x = 0.24

The equilibrium concentration of = (0.4-x) = (0.4-0.24) = 0.16 M

Therefore, the equilibrium concentration of is, 0.16 M