Consider the reactions:
a) `H_3 PO_2(aq)+4 AgNO_3(aq)+2 H_2 O(l) rarr H_3 PO_4(aq)+4 Ag(s)+4 HNO_3(aq)`
b) `H_3 PO_2(aq)+2 CuSO_4(aq)+2 H_2 O(l) rarr H_3 PO_4(aq)+2 Cu(s)+H_2 SO_4(aq)`
c) `C_6 H_5 CHO(l)+2[Ag(NH_3)_2]^+(a, q)(+3) OH^-(aq) rarr C_6 H_5 COO^-(aq)+2Ag(s)+4 NH_3(a q)+2 H_2 O(l)`
d) `C_6 H_5 CHO(l)+2Cu^(2+)(aq)+5 OH^-(aq) rarr` No change observed.
What inference do you draw about the behaviour of `Ag^+` and `Cu^((2+))` from these reactions?