State the kind of chemical reactions in the following examples `:`
(i) Digestion of food in stomach
(ii) Combustion of coal in air
(iii) Heating of limestone.

Explanation

(i) Digestion of food in stomach . During digestion, the complex food is broken into simpler form. Therefore, it is a type of decomposition reaction.
(ii) Combustion of coal in air. During combustion the coal burns in air to form `CO_(2), H_(2)O` along with the evolution of heat. Thus, it is a type of exothermic decomposition reaction.
(iii) Heating of limestone. When limestone is heated strongly, it breaks into `CO_(2)` and lime. Thus, it is a type of thermal decompositin reaction.