Question

$\mathit{A}{\mathit{l}}_{\mathbf{2}}{\mathit{O}}_{\mathbf{3}}$is amphoteric. What does this mean?

Short answer

$A{l}_2{O}_3$has properties of both acids and bases.

Step-by-step solution

Definition of amphoteric

A molecule or ion that may react as both an acid and a base is known as an amphoteric substance.

The meaning of amphoteric

The compound exhibits characteristics of both acids and bases, $A{l}_2{\mathrm{O}}_3$ is categorised as an amphoteric oxide.

By interacting with acids, it shows basic properties:

${\text{Al}}_2{\text{O}}_3\left(s\right)+6\text{HCl}\left(aq\right)\to 2{\text{AlCl}}_3\left(aq\right)+3{\text{H}}_2\text{O}\left(l\right)$

It also reacts with bases to produce acidic properties:

${\text{Al}}_2{\text{O}}_3\left(s\right)+2\text{NaOH}\left(aq\right)+3{\text{H}}_2\text{O}\left(l\right)\to 2\text{NaAl}(\text{OH}{)}_4\left(aq\right)$