A metal 'X' is used in thermite process. When X is burnt in air it gives an amphoteric oxide 'Y'. 'X' and 'Y' are respectively:

Aluminium ($\mathrm{Al}$) is a metal used in the thermite process (for reducing metal oxides like iron oxide). When aluminium is heated or burnt in air, it combines with oxygen to form aluminium oxide ($\mathrm{Al}_2\mathrm{O}_3$), which is an amphoteric oxide because it reacts with both acids and bases to produce salt and water.

• Option a is incorrect because iron oxide ($\mathrm{Fe}_2\mathrm{O}_3$) is a basic oxide, not an amphoteric oxide.
• Option b is correct because aluminium ($\mathrm{Al}$) forms the amphoteric oxide $\mathrm{Al}_2\mathrm{O}_3$.
• Option c is incorrect because iron oxide ($\mathrm{Fe}_3\mathrm{O}_4$) is basic, not amphoteric.
• Option d is incorrect because the chemical formula of aluminium oxide is $\mathrm{Al}_2\mathrm{O}_3$, not $\mathrm{Al}_3\mathrm{O}_4$.