Chemical Changes and Reactions — Question 14

(a) The chemical reaction in which a compound splits into two or simpler substances (elements or compounds) is called decomposition reaction.

(b) Two balanced chemical equations for:

(i) Heat

2HgO (s) $\xrightarrow{\Delta}$ 2Hg (l) + O₂ (g)

CaCO₃ (s) $\xrightarrow{\Delta}$ CaO (s) + CO₂ (g)

(ii) Electricity

2NaCl (l) $\xrightarrow{\text{electricity}}$ 2Na (l) + Cl₂ (g)

2H₂O (l) $\xrightarrow{\text{electricity}}$ 2H₂ (g) + O₂ (g)

(iii) Light

2AgCl (s) $\xrightarrow{\text{ sunlight}}$ 2Ag (s) + Cl₂ (g)

2H₂O₂ (l) $\xrightarrow{\text{ sunlight}}$ 2H₂O (l) + O₂ (g)