Aluminium dissovles in mineral acids and aqueous alkalies and thus shows amphoteric character. A place of aluminum foil is treated with dilute hydrochloric acid or dilute sodium hydroxide solution in a test tube and on bringing a burning match stick near the mouth of the test tube, a pop sound indicates the evolution of hydrogen gas. The same activity when performed with concentrated with concentrated nitric acid. reaction doesn't proceed. Expalin the reason.

Explanation

Aluminium is a reactive metal and evolves hydrogen gas on reacting with dilute `HCl` as well as dilute NaOH solution.
`2Al(s)+3HCl(aq)rarr2AlCl_(3)(aq)+3H_(2)(g)`
`2Al(s)+2NaOH(aq)+6H_(2)O(l)rarr2Na^(+)[Al(OH)_(4)]^(-)(aq)+3H_(2)(g)`
However, with concentrated nitric acid, aluminium does not react. Actually the metal is oxididwed initially to its oxide `(Al_(2)O_(3))`. This gets deposited as a layer on the surface of the metal. it is passive towards acids. Therefore, the metal does not react with conc. `HNO_(3)`.