Question

Consider the following reaction:
$HCHO +2\left[ Ag \left( NH _3\right)_2\right]^{+}+3 OH ^{-} \longrightarrow 2 Ag + HCOO ^{-} +4 NH _3+2 H _2 O$
Which of the following statements regarding oxidation and reduction is correct?

• A. $HCHO$ is oxidised to $HCOO^-$ and $[Ag(NH_3)_2]^+$ is reduced to $Ag$.
• B. $HCHO$ is reduced to $HCOO^-$ and $[Ag(NH_3)_2]^+$ is oxidised to Ag.
• C. $[Ag(NH_3)_2]^+$ is reduced to $Ag$ while $OH^-$ is oxidised to $HCOO^-$
• D. $[Ag(NH_3)_2]^+$ is oxidised to $NH_3$ while $HCHO$ is reduced to $H_2O$.

Answer 1

Answer: (A)

$HCHO + 2[Ag(NH_3)_2]^+ + 3OH^- \rightarrow 2Ag + HCOO^{-} + 4NH_3 + 2H_2O$
$HCHO \to HCOO^-$ (oxidation)
$[Ag(NH_3)_2]^+ \to Ag$ (reduction)