Question

The pair of amphoteric oxides is:

• A. $\mathrm{BeO}\mathrm{and}{\mathrm{BO}}_3$
• B. $\mathrm{BeO}\mathrm{and}\mathrm{MgO}$
• C. $\mathrm{BeO}\mathrm{and}\mathrm{ZnO}$
• D. ${\mathrm{Al}}_2{\mathrm{O}}_3\mathrm{and}{\mathrm{Li}}_2\mathrm{O}$

Answer 1

The correct option is C

$\mathrm{BeO}\mathrm{and}\mathrm{ZnO}$

The explanation for the correct option

(C) $\mathbf{BeO}\mathbf{}\mathbf{and}\mathbf{}\mathbf{ZnO}$

Amphoteric oxide

• Amphoteric oxides are those metal oxides that can react with both acid and base.

Explanation:

• Both $\mathrm{BeO}\mathrm{and}\mathrm{ZnO}$can react with both acid and base.
• $$\begin{gathered} \mathrm{BeO}+2\mathrm{HCl}\to {\mathrm{BeCl}}_2+{\mathrm{H}}_2\mathrm{O} \\ \left(\mathrm{acid}\right) \end{gathered}$$
• $$\begin{gathered} \mathrm{BeO}+2\mathrm{NaOH}\to {\mathrm{Na}}_2{\mathrm{BeO}}_2+{\mathrm{H}}_2\mathrm{O} \\ \left(\mathrm{base}\right) \end{gathered}$$
• $$\begin{gathered} \mathrm{ZnO}+2{\mathrm{HNO}}_3\to \mathrm{Zn}{\left({\mathrm{NO}}_3\right)}_2+{\mathrm{H}}_2\mathrm{O} \\ \left(\mathrm{acid}\right) \end{gathered}$$
• $$\begin{gathered} \mathrm{ZnO}+2\mathrm{NaOH}\to {\mathrm{Na}}_2{\mathrm{ZnO}}_2+{\mathrm{H}}_2\mathrm{O} \\ \left(\mathrm{base}\right) \end{gathered}$$

The explanation for the incorrect options

(A) $\mathbf{BeO}\mathbf{}\mathbf{and}\mathbf{}{\mathbf{BO}}_{\mathbf{3}}$

• ${\mathrm{BO}}_3$ is not an amphoteric compound.
• Hence, $\mathrm{BeO}\mathrm{and}{\mathrm{BO}}_3$ not a pair of amphoteric oxide.

(B) $\mathbf{BeO}\mathbf{}\mathbf{and}\mathbf{}\mathbf{MgO}$

• $\mathrm{MgO}$ is basic in nature and does not shows acidic nature.
• Hence, $\mathrm{BeO}\mathrm{and}\mathrm{MgO}$ not a pair of amphoteric oxide.

(D) ${\mathbf{Al}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{3}}\mathbf{}\mathbf{and}\mathbf{}{\mathbf{Li}}_{\mathbf{2}}\mathbf{O}$

• ${\mathrm{Al}}_2{\mathrm{O}}_3$is an amphoteric oxide.
• While ${\mathrm{Li}}_2\mathrm{O}$is basic in nature and does not shows acidic nature.
• Hence, ${\mathrm{Al}}_2{\mathrm{O}}_3\mathrm{and}{\mathrm{Li}}_2\mathrm{O}$ not a pair of amphoteric oxide.

Therefore, the pair of amphoteric oxide is an option (C): $\mathbf{BeO}\mathbf{}\mathbf{and}\mathbf{}\mathbf{ZnO}$