How Alkyl iodides are prepared?

Explanation

(i) `underset((""Calcium carbonate"))(CaCO_(3)) underset(Delta)overset(1200K)tounderset(("Quick Lime"))(CaO+CO_(2))`
(ii) `underset(("Gypsum"))(CaSO_(4)).2H_(2)O overset(390K)tounderset(("Plaster of Paris"))(CaSO_(4).1//2H_(2)O) underset(470K)overset("Above")tounderset(("Dead burnt plaster"))(CaSO_(4))`
(iii) `underset(("Magnesium chloride hexahydrate"))(MgCl_(2).6H_(2)O) overset("Heat")to MgO+2HC l+5H_(2)O`
(iv) `underset(("Magnesium sulphate hepta hydrate"))(MgSO_(4).7H_(2)O) underset(-6H_(2)O)overset(423K)toMgSO_(4).H_(2)O underset(-H_(2)O)overset(503K)toMgSO_(4)overset("Heat")toMgO+underset(("Magnesium oxide"))(SO_(3))`