Question

Balance each of the following examples of heterogeneous equilibria and write each Kc expression. Then calculate the value of Kc for the reverse reaction.

(1) Al(s) + NaOH(aq) + H2O(l) ⇋ Na[Al(OH)4](aq) + H2(g) Kc for balanced reaction = 11
(2) H2O(l) + SO3(g) ⇋ H2SO4 (aq) Kc for balanced reaction = 0.0123
(3) P4(s) + O2(g) ⇋ P4O6(s) Kc for balanced reaction = 1.56

Answer 1

Step-by-step explanation:

1)
`2 Al(s) + 2 NaOH(aq) + 6 H_2O(l) \longleftrightarrow 2 Na[Al(OH)_4](aq) + 7 H_2(g)`

`Kc=([Na[Al(OH)_4]]^2*[H_2]^7)/([NaOH]^2)`

The Kc for the reverse reaction is the inverse of the Kc of the reaction:

`Kc_(reverse)=(1)/(Kc)=(1)/(11)=0.091`

2)
`H_2O(l) + SO_3(g) \longleftrightarrow H_2SO_4 (aq)`

`Kc=([H_2SO_4])/([SO_3]^2)`

The Kc for the reverse reaction is the inverse of the Kc of the reaction:

`Kc_(reverse)=(1)/(Kc)=(1)/(0.0123)=81.3`

3)
`P_4(s) + 3 O_2(g) \longleftrightarrow P_4O_6(s)`

`Kc=(1)/([O_2]^3)`

The Kc for the reverse reaction is the inverse of the Kc of the reaction:

`Kc_(reverse)=(1)/(Kc)=(1)/(1.56)=0.641`