Question

A metal A, which is used in thermite process, when heated with oxygen gives an oxide B, which is amphoteric in nature. Identify A and B. Write down the reactions of oxide B with HCl and NaOH. 

Answer 1

Matel A is aluminium (Al) which is used in thermite process.
Al reacts with oxygen to from aluminium oxide `Al_(2)O_(3)` (B) which is amphoteric in nature.
`4Al+3O_(2)tounderset((B))(2Al_(2)O_(3)(s))`
`(i)underset("Aluminium oxide")(Al_(2)O_(3)(s))+underset("Hydrochioric acid")(6HCl(aq))tounderset("Aluminium chloride")(2AlCl_(3)(aq))+3H_(2)O(l)`
`(ii)underset("Aluminium oxide")(Al_(2)O_(3))+underset("Hydrochioric acid")(2NaOH(aq))tounderset("Sodium aluminate")(2NaAlO_(2)(aq))+3H_(2)O(l)`