Question

7. For the system PCls(g) → PC13(g) + Cl2(g) Kis 26 at 300°C. In a 5.0-L flask, a gaseous mixture consists of all three gases with partial pressure as follows: Ppcis = 0.012 atm, Pc2=0.45 atm, Ppci3 -0.90 atm. a) Is the mixture at equilibrium? Explain. b) If it is not at equilibrium, which way will the system shift to establish equilibrium?

Answer 1

a) Reaction is not at equilibrium

b) Reaction will move towards backward direction

Step-by-step explanation:

`PCl_5(g) \rightarrow PCl_3(g) + Cl_2(g)`

Equilibrium constant = 26

`Reaction\ quotient (Q) = ([p_(PCl_3)]* [p_(Cl_2)])/([p_(PCl_5)])`

`[p_(PCl_5)] = 0.012 atm`

`[p_(PCl_3)]= 0.90 atm`

`[p_(Cl_2)]= 0.45 atm`

`Reaction\ quotient (Q) = ([p_(PCl_3)]* [p_(Cl_2)])/([p_(PCl_5)])`

`Reaction quotient (Q) =\frac{0.90* 0.45} {0.012} = 33.75`

As reaction quotient (Q) is more than equilibrium constant, so reaction is not at equilibrium and reaction will move towards backward direction.