Question

Consider the reactions:

1. H3PO2(aq) + 4 AgNO3(aq) + 2 H2O(l) $\rightarrow$ H3PO4(aq) + 4Ag(s) + 4HNO3(aq)
2. H3PO2(aq) + 2CuSO4(aq) + 2 H2O(l) $\rightarrow$ H3PO4(aq) + 2Cu(s) + H2SO4(aq)
3. C6H5CHO(l) + 2[Ag (NH3)2]+(aq) + 3OH- (aq) $\rightarrow$ C6H5COO- (aq) + 2Ag(s) + 4NH3(aq) + 2 H2O(l)
4. C6H5CHO(l) + 2Cu2+(aq) + 5OH-(aq) $\rightarrow$ No change observed.

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

Answer 1

$Ag ^+$ and $Cu ^{2+}$ act as oxidising agents in reactions (a) and (b) respectively.
In reaction (c), $Ag ^+$ oxidises $C_6H_5CHO$ to $C_6H_5COO ^-$ , but in reaction (d), $Cu ^{2+}$ cannot oxidise $C_6H_5CHO$.

Hence, we can say that $Ag ^+$ is a stronger oxidising agent than $Cu^{ 2+}$ .