Problems
1. If Kc for the equation,
find out Kc_{I }and Kc_{II} for
Solution :
2) When 0.4 mole of PCl5 is heated to 523 K in a 10 dm3 container, an equilibrium is established in which 0.25 mole Cl2 is present.
Find out K_{c} for the dissociation of PCl_{5} at 523 K.
Initially 0.4 mole 0 mole 0 mole
At equili. (0.4  0.25) 0.25 mole 0.25 mole
3) The equilibrium constant KP for the dissociation
of PCl_{5} at 523 K and 101.3 KP_{a} pressure is
180.3. Calculate its percent dissociation at 523 K.
Initially 1 mole 0 mole 0 mole
At equilibrium (1  x) mole x mole x mole
(Total number of moles at equilibrium = 1 x + x + x = 1+ x )
If P is total pressure then partial pressure at equilibrium
180.3  180.3x2 = x2 ´ 101.3
101.3x2 + 180.3x2 = 180.3
\ x2^{ }=
0.64 \ x = 0.8
Percent dissociation = 0.8 ´ 100 = 80%
