Q.Show, with balanced equations, that aluminium oxide $\text{Al}_2\text{O}_3$ is amphoteric. Name two everyday or industrial uses of $\text{Al}_2\text{O}_3$.

[!TLDR] Al2O3 reacts with both acid and base, confirming its amphoteric nature; it is used as an abrasive and as a refractory lining. [!ANSWER] $\text{Al}_2\text{O}_3+6\text{HCl}\rightarrow 2\text{AlCl}_3+3\text{H}_2\text{O}$ and $\text{Al}_2\text{O}_3+2\text{NaOH}\rightarrow 2\text{NaAlO}_2+\text{H}_2\text{O}$; it is used …

Aluminium oxide, $\text{Al}_2\text{O}_3$, reacts with both a strong acid and a strong base, which is the defining test of an amphoteric oxide. With dilute hydrochloric acid it dissolves to give aluminium chloride and water:\n$\text{Al}_2\text{O}_3 + 6\text{HCl} \longrightarrow 2\text{AlCl}_3 + 3\text{H}_2\text{O}$\nWith aqueous sodium hydroxide it likewise dissolves, this time forming sodium aluminate and water:\n$\text{Al}_2\text{O}_3 + 2\text{NaOH} \longrightarrow 2\text{NaAlO}_2 + \text{H}_2\text{O}$\nBecause it reacts as a base towards the acid and as an acid towards the base, $\text{Al}_2\text{O}_3$ is confirmed as amphoteric. In its hard, chemically inert crystalline form (corundum), $\text{Al}_2\text{O}_3$ is put to substantial practical use: its extreme hardness makes it valuable as an abrasive for cutting, grinding and polishing, and its very high melting point and chemical stability make it an excellent refractory lining material for high-temperature industr …

Write balanced equations showing Al2O3 reacting with both an acid and a base to demonstrate amphoter …

Showing reaction with only acid or only base rather than both, which is needed to actually demonstrate amphoteric behaviour; conf …