Amphoteric substances will be substances that display both acidic and essential characteristics. Since aluminum breaks up in the two acids and bases, it is said to have an amphoteric nature.

(I)

$2 A l_{(s)}+6 H C l_{(a q)} \rightarrow 2 A l_{(a q)}^{3+}+6 C l_{(a q)}^{-}+3 H_{2(g)}$

(ii)

$2 \mathrm{Al}_{(s)}+2 \mathrm{NaOH}_{(a q)}+6 \mathrm{H}_{2} \mathrm{O}_{(l)} \rightarrow 2 \mathrm{Na}^{+}\left[\mathrm{Al}(\mathrm{OH})_{4}\right]_{(a q)}^{-}+3 H_{2(g)}$