Explain : 'Silver nitrate solution is kept in coloured reagent bottles in the laboratory.'

Reactions can be classified as : Direct combination, decomposition, simple displacement, double decomposition, Redox reactions. State which of the following types, takes place in the reactions given below

(i) CI₂ + 2KI ⟶ 2KCl + l₂

(ii) 2Mg + O₂ ⟶ 2MgO

(iii) SO₂ + 2H₂O + Cl₂ ⟶ 2HCl + H₂SO₄

(iv) AgNO₃ + HCl ⟶ AgCl + HNO₃

(v) 4HNO₃ ⟶ 4NO₂ + 2H₂O + O₂

Give an example of a photochemical decomposition reaction.

Name a metallic oxide which on thermal decomposition is reduced to a metal.