Question

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

Answer 1

(a) Thermal decomposition is a chemical reaction where a single substance breaks into two or more simple substances when heated.
2FeSO_4(s)              \(\xrightarrow{Δ}\)       FeO3(s)            +       SO2(g)                 +      SO3(g)
(Ferrous sulphate)        (Ferric oxide)         (Sulphur Oxide)        (Sulphur trioxide)

(b) Photo decomposition is a chemical reaction in which a substance is broken down into simple substances by exposure to light (photons)
2AgCl_(s)       \(\xrightarrow{light}\)        2Ag_(s)    +     Cl_2(g)
(Silver chloride)         (Silver)           (Chlorine)

(c) Electrolytic decomposition may result when the electric current is passed through an aqueous solution of a compound. 
2Al₂O_3(aq)            \(\xrightarrow{ Electricity}\)    4AI_(s)             +    3O_2(g)
(Aluminium Oxide)                  (Aluminium)         (Oxygen)