Briefly explain how the following s-block compounds can be prepared
(i) MgO can be produced by burning magnesium metal in oxygen.
2Mg + O2 2MgO
However, this is rather expensive and dangerous.
Large amounts of MgO are obtained fro sea water (Magnesium chloride) by treating it with lime water to precipitate magnesium ions as Mg(OH)2;
Mg2+ + Ca(OH)2 Mg(OH)2 + Ca2+
Magnesium oxide is then roasted (Calcination) at varying temperatures to produce MgO;
Mg(OH)2 MgO + H2O
(ii) NaCl can also be produced by reacting the elements sodium and chlorine;
2Na + Cl2 2NaCl
However, the reaction is also expensive and dangerous. Otherwise, mass production of NaCl is by evaporation of sea water to saturation and crystallization of the solid crystals.