Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.

Decomposition may occur in the presence of Heat or Light or by the passage of an Electric Current.
Heat light and electricity are different forms of energy which cause breaking of bonds in the molecule of reactants to yield simpler products.
(a)The compound calcium carbonate when heated, decomposes to form two elements, calcium oxide and carbon dioxide
$$ CaCO_{3} (s) \rightarrow CaO (s) + CO_{2} (g) $$
In this reaction energy is supplied in the form of heat.
(b)When silver chloride is exposed to sunlight it undergoes photochemical decomposition forming silver and chlorine.
$$ 2AgCl (s) + sunlight \rightarrow 2Ag(s) + Cl_{2}(g) $$
In this reaction energy is supplied in the form of light,i.e.sunlight
(c)When electric current is passed through water,the latter decomposes into hydrogen and oxygen.
$$ 2H_{2}O + electricity \rightarrow 2H_{2} + O_{2} $$
In this reaction energy is supplied in the form of electricity.