Question

A mixture of 1.6 mol of PCl 5 , 0.92 mol of Cl 2 and 0.78 mol of PCl 3 is introduced
into a 20.0 L reaction vessel at 500K. At this temperature, the equilibrium
constant Kc for the reaction: PCl 5 (g) = PCl 3 (g) + Cl 2 (g) is 1.8 × 10 -3 . Is the
reaction mixture at equilibrium? If not what is the direction of the net reaction?

Answer 1

Answer:

The given reaction is :-

PCl

5

(g)⇌PCl

3

(g)+Cl

2

(g)

Initial moles : 1.6 0 0 (given)

At eqm : 1.2 0.4 0.4 (given)

Now, conc. of PCl

5

at equation =

4

1.6

mole/dm

3

conc. of PCl

3

at equation =

4

0.4

mole/dm

3

conc. of Cl

2

at equation =

4

0.4

mole/dm

3

∴K

C

=

[PCl

5

]

[PCl

3

][Cl

2

]

=

0.4

0.1×0.1