Question

Zinc oxide and Aluminum oxide are ___ oxides.

Answer 1

The oxide of Aluminium is ${\mathbf{Al}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{3}}$ and the oxide of Zinc is $\mathbf{ZnO}$.

• When Aluminium Oxide reacts with Hydrochloric acid it forms Aluminium Chloride and Water.

$$\begin{gathered} {\mathbf{Al}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{3}}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{6}\mathbf{HCl}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}\mathbf{2}{\mathbf{AlCl}}_{\mathbf{3}}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{3}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{}\mathbf{\left(}\mathbf{l}\mathbf{\right)} \\ \mathbf{Aluminium}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Aluminium} \\ \mathbf{Oxide}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Cholride} \end{gathered}$$

In this reaction, Aluminium Oxide behave as a basic.

• When Aluminium oxide reacts with Sodium hydroxide to form Sodium Aluminate and water.

$$\begin{gathered} \mathbf{}\mathbf{}{\mathbf{Al}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{3}}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{2}\mathbf{NaOH}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}\mathbf{2}{\mathbf{NaAlO}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{}\mathbf{\left(}\mathbf{l}\mathbf{\right)} \\ \mathbf{Aluminium}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Sodium}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Sodium}\mathbf{}\mathbf{Aluminate} \\ \mathbf{oxide}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Hydroxide} \end{gathered}$$

In this reaction, Aluminium Oxide behave as an acidic oxide.

• When Zinc oxide reacts with Hydrochloric acid to form Zinc Chloride and water.

$$\begin{gathered} \mathbf{ZnO}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{2}\mathbf{HCl}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}{\mathbf{ZnCl}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{}\mathbf{\left(}\mathbf{l}\mathbf{\right)} \\ \mathbf{Zinc}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Hydrochloric}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Zinc}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{} \\ \mathbf{Oxide}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Acid}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Chloride} \end{gathered}$$

In this reaction, Zinc Oxide behave as a basic.

• When Zinc oxide reacts with Sodium hydroxide to form Sodium Zincate and water.

$$\begin{gathered} \mathbf{ZnO}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{2}\mathbf{NaOH}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}{\mathbf{Na}}_{\mathbf{2}}{\mathbf{ZnO}}_{\mathbf{2}}\mathbf{}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{}\mathbf{\left(}\mathbf{l}\mathbf{\right)} \\ \mathbf{Zinc}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Sodium}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Sodium}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{} \\ \mathbf{Oxide}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Hydroxide}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{Zincate} \end{gathered}$$

In this reaction, Zinc Oxide behaves as an acidic oxide.

• The oxide of Aluminum and Zinc shows both acidic as well as basic properties.

Therefore, Zinc oxide and Aluminum oxide are amphoteric oxides.

• The oxide which behaves both as acid and base and can react with both acid and base is termed amphoteric oxide.