Extraction of metals and properties of ionic compounds

(I) Extraction of Hg from Cinnabar (HgS): $2\text{HgS}(s) + 3\text{O}_2(g) \xrightarrow{\Delta} 2\text{HgO}(s) + 2\text{SO}_2(g)$ $2\text{HgO}(s) \xrightarrow{\Delta} 2\text{Hg}(l) + \text{O}_2(g)$

(II) Extraction of Zn from Calamine ($\text{ZnCO}_3$): $\text{ZnCO}_3(s) \xrightarrow{\Delta} \text{ZnO}(s) + \text{CO}_2(g) \quad \text{(Calcination)}$ $\text{ZnO}(s) + \text{C}(s) \rightarrow \text{Zn}(s) + \text{CO}(g) \quad \text{(Reduction)}$

(III) Extraction of Na from molten NaCl: $2\text{NaCl}(l) \xrightarrow{\text{Electrolysis}} 2\text{Na}(s) \text{ [at Cathode]} + \text{Cl}_2(g) \text{ [at Anode]}$

(I) In solid state, ions are held in fixed positions by strong electrostatic forces and cannot move. (II) A large amount of energy is required to break the strong inter-ionic electrostatic forces of attraction holding the lattice.