Consider the reactions:
(a) H₃PO₂(aq) + 4 AgNO₃(aq) + 2 H₂O(l) → H₃PO₄(aq) + 4Ag(s) + 4HNO₃(aq)

(b) H₃PO₂(aq) + 2CuSO4(aq) + 2H₂O(l) → H₃PO₄(aq) + 2Cu(s) + H₂SO₄(aq)

(c) C₆H₅CHO(l) + 2[Ag (NH₃)₂]⁺(aq) + 3OH^–(aq) → C₆H₅COO^–(aq)+ 2Ag(s) +4NH₃ (aq) + 2H₂O(l)

(d) C₆H₅CHO(l) + 2Cu²⁺(aq) + 5OH^–(aq) → No change observed.

What inference do you draw about the behaviour of Ag⁺ and Cu²⁺ from these reactions ?

Discuss briefly the types of redox reactions. Give examples. 
or
Discuss the following redox reactions.
(a) Combination reactions
(b) Decomposition reactions
(c) Displacement reactions
(d) Disproportionation reactions.
Give one example in each case.

Suggest a scheme of classification of the following redox reactions:
(a) N₂(g) + O₂(g) → 2 NO (g)
(b) 2Pb(NO₃)₂(s) → 2PbO(s) + 2 NO₂ (g) + ½ O₂ (g)
(c) NaH(s) + H₂O(l) → NaOH(aq) + H₂ (g)
(d)2NO₂(g) + 2OH^–(aq) → NO2^-(aq) +NO₃^–(aq)+H₂O(l)

Refer to the periodic table given in your book and now answer the following questions:
(a) Select the possible non-metals that can show disproportionation reaction.
(b) Select three metals that can show disproportionation reaction.

What sorts of informations can you draw from the following reaction?
(CN)₂(g) + 2OH^– (aq) → CN^–(aq) + CNO^–(aq) + H₂O(l)

Suggest a scheme of classification of the given redox reactions,

 N₂ (g) + O₂ (g)  2NO (g)