Question

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

• A. $HCHO$ is oxidised to $HCO{O}^{-}$ and $[Ag(N{H}_3{)}_2{]}^{+}$ is reduced to $Ag$.
• B. $HCHO$ is reduced to $HCO{O}^{-}$ and $[Ag(N{H}_3{)}_2{]}^{+}$ is oxidised to Ag.
• C. $[Ag(N{H}_3{)}_2{]}^{+}$ is reduced to $Ag$ while $O{H}^{-}$ is oxidised to $HCO{O}^{-}$
• D. $[Ag(N{H}_3{)}_2{]}^{+}$ is oxidised to $N{H}_3$ while $HCHO$ is reduced to $H_{2}O$.

Answer 1

Answer: (A)

$HCHO+2[Ag(N{H}_3{)}_2{]}^{+}+3O{H}^{-}\to 2Ag+HCO{O}^{-}+4N{H}_3+2H_{2}O$
$HCHO\to HCO{O}^{-}$ (oxidation)
$[Ag(N{H}_3{)}_2{]}^{+}\to Ag$ (reduction)