Question

Consider the reactions: 

(a) H₃PO_2(aq) + 4AgNO_3(aq) + 2H₂O_(l) → H₃PO_4(aq) + 4Ag_(s) + 4HNO_3(aq) 

(b) H₃PO_2(aq) + 2CuSO_4(aq) + 2H₂O_(l) → H₃PO_4(aq) + 2Cu_(s) + H₂SO_4(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? 

Answer 1

Ag⁺ and Cu²⁺ act as oxidising agents in reactions (a) and (b) respectively. 

In reaction (c), Ag⁺ oxidises C₆H₅CHO to C₆H₅COO^– , but in reaction (d), Cu²⁺ cannot oxidise C₆H₅CHO. Hence, we can say that Ag⁺ is a stronger oxidising agent than Cu²⁺