Question

Ammonia can act as a reducing agent-write a relevant equation for such a reaction.

Answer 1

Reducing agents have defined as the compounds that themselves undergo oxidation but reduce the other species in a chemical reaction

Ammonia$\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}$ can act as a reducing agent. It can be shown by the following chemical equation as

$$\begin{gathered} 3\mathrm{CuO}\left(\mathrm{s}\right)+2{\mathrm{NH}}_3\left(\mathrm{g}\right)\to 3\mathrm{Cu}\left(\mathrm{s}\right)+{\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ \mathrm{Copper}\mathrm{Ammonia}\mathrm{Copper}\mathrm{Nitrogen}\mathrm{Water} \\ \mathrm{oxide}\mathrm{gas}\mathrm{metal}\mathrm{gas} \end{gathered}$$

In this reaction, when dry ammonia gas is passed over heated black copper oxide$\mathbf{\left(}\mathbf{CuO}\mathbf{\right)}$, it will be reduced to brown copper$\mathbf{\left(}\mathbf{Cu}\mathbf{\right)}$. Ammonia gas reduces the copper oxide to copper metal. Hence, here ammonia gas act as a reducing agent.