What is heterogeneous equilibrium? Give its types with examples.

Equilibrium in a system having more than one phase is called heterogeneous equilibrium.
Type-$1$: Liquid $\rightleftharpoons$ Gas
Example: $H_2O_{(l)} \rightleftharpoons H_2O_{(g)}$
Type-$2$: Solid $\rightleftharpoons$ Aqueous solution
Example: $Ca(OH)_{2(s)} \rightleftharpoons Ca^{2+}_{(aq)} + 2OH^-_{(aq)}$
Example: $C_{12}H_{22}O_{11(s)} \rightleftharpoons C_{12}H_{22}O_{11(aq)}$
Type-$3$: Solid $\rightleftharpoons$ Gas
Example: $CaCO_{3(s)} \rightleftharpoons CaO_{(s)} + CO_{2(g)}$
Example: $NH_4Cl_{(s)} \rightleftharpoons NH_{3(g)} + HCl_{(g)}$
Example: $C_{(s)} + CO_{2(g)} \rightleftharpoons 2CO_{(g)}$