(N/A) Aluminum is amphoteric in nature; it reacts with acids and bases to produce salt and $H_{2}$ gas. The evolution of $H_{2}$ gas is confirmed by the pop sound produced when a burning matchstick is brought near the mouth of the test tube.
$2 Al(s) + 6 HCl(aq) \rightarrow 2 AlCl_{3}(aq) + 3 H_{2}(g)$
$2 Al(s) + 2 NaOH(aq) + 6 H_{2}O(l) \rightarrow 2 Na[Al(OH)_{4}](aq) + 3 H_{2}(g)$
When $Al$ reacts with concentrated $HNO_{3}$,a thin,non-porous,and inert layer of aluminum oxide $(Al_{2}O_{3})$ forms on the surface of the metal. This layer acts as a protective barrier,preventing further reaction between the metal and the acid,a phenomenon known as passivation.