Question

Which of the systems described in Exercise 13.16 give homogeneous equilibria? Which give heterogeneous equilibria?

(a) \({N_2}(g) + 3{H_2}(g)\rightleftharpoons 2N{H_3}(g)\)

(b) \(4N{H_3}(g) + 5{O_2}(g)\rightleftharpoons 4NO(g) + 6{H_2}O(g)\)

(c) \({N_2}{O_4}(g)\rightleftharpoons 2N{O_2}(g)\)

(d) \(C{O_2}(g) + {H_2}(g)\rightleftharpoons CO(g) + {H_2}O(g)\)

(e) \(N{H_4}Cl(s)\rightleftharpoons N{H_3}(g) + HCl(g)\)

(f) \(2\;Pb{\left( {N{O_3}} \right)_2}(s)\rightleftharpoons 2PbO(s) + 4N{O_2}(g) + {O_2}(g)\)

(g) \(2{H_2}(g) + {O_2}(g)\rightleftharpoons 2{H_2}O(l)\)

(h) \({S_8}(g)\rightleftharpoons 8\;S(g)\)

Short answer

1. The system is Homogenous.
2. The system is Homogenous.
3. The system is Homogenous.
4. The system is homogenous.
5. The system is Heterogenous.
6. The system is heterogeneous.
7. The system is Heterogenous.
8. The system is homogenous.

Step-by-step solution

Definition of equilibria

When reactants and products are in different phases in a chemical reaction, heterogeneous equilibria is obtained, and when they are in the same phase, homogeneous equilibria is obtained.

Find the system of equilibriafor part (a)

a.

The given system is:

\({{\rm{N}}_2}(\;{\rm{g}}) + 3{{\rm{H}}_2}(\;{\rm{g}})\rightleftharpoons 2{\rm{N}}{{\rm{H}}_3}(\;{\rm{g}})\)

Both reactant and product are in same phase, i.e. in the gaseous phase. So, the system is in homogenous equilibria.

Determine the system of equilibriafor part (b)

b.

The given system is:

\(4{\rm{N}}{{\rm{H}}_3}(\;{\rm{g}}) + 5{{\rm{O}}_2}(\;{\rm{g}})\rightleftharpoons 4{\rm{NO}}({\rm{g}}) + 6{{\rm{H}}_2}(\;{\rm{g}})\)

Here both reactant and product are in same phase, i.e. in the gaseous phase. So, the system is in homogenous equilibria.

Detect the system of equilibriafor part (c)

C.

The given system is:

\({{\rm{N}}_2}{{\rm{O}}_4}(\;{\rm{g}})\rightleftharpoons2{\rm{N}}{{\rm{O}}_2}(\;{\rm{g}})\)

Both reactant and product are in same phase, i.e. in the gaseous phase. So, the system is in homogenous equilibria.

Discover the system of equilibriafor part (d)

d.

The given system is:

\({\rm{C}}{{\rm{O}}_2}(\;{\rm{g}}) + {{\rm{H}}_2}(\;{\rm{g}})\rightleftharpoons {\rm{CO}}({\rm{g}}) + {{\rm{H}}_2}{\rm{O}}({\rm{g}})\)

Both reactant and product are in same phase, i.e. in the gaseous phase. So, the system is in homogenous equilibria.

Determine the system of equilibriafor part (e)

e.

The given system is:

\({\rm{N}}{{\rm{H}}_4}{\rm{Cl}}({\rm{s}}) \rightleftharpoons {\rm{N}}{{\rm{H}}_3}(\;{\rm{g}}) + {\rm{HCl}}({\rm{g}})\)

The phases of reactant and product are different, i.e. solid and gas. So, the system is in heterogeneous equilibrium.

Detect the system of equilibriafor part (f)

F.

The given system is:

\(2\;{\rm{Pb}}{\left( {{\rm{N}}{{\rm{O}}_3}} \right)_2}(\;{\rm{s}})\rightleftharpoons 2{\rm{PbO}}({\rm{s}}) + 4{\rm{N}}{{\rm{O}}_2}(\;{\rm{g}}) + {{\rm{O}}_2}(\;{\rm{g}})\)

The phases of reactant and product are different, i.e. solid and gas. So, the system is in heterogeneous equilibrium.

Find the system of equilibriafor part (g)

g.

The given system is as follows:

\(2{{\rm{H}}_2}(\;{\rm{g}}) + {{\rm{O}}_2}(\;{\rm{g}})\rightleftharpoons 2{{\rm{H}}_2}{\rm{O}}({\rm{l}})\)

The phases of reactant and product are different, i.e. solid and gas. So, the system is in heterogeneous equilibrium.

Discover the system of equilibriafor part (h)

h.

The given system is:

\({{\rm{S}}_8}(\;{\rm{g}})\rightleftharpoons 8\;{{\rm{S}}_8}(\;{\rm{g}})\)

Both reactant and product are in same phase, i.e. in the gaseous phase. So, the system is in homogenous equilibria.