Question

Question 46
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

Thermite process is the reduction of metal oxides with aluminium, producing a large amount of heat. This is generally used in the welding of metal parts.

$\text{A}-\text{Al};\text{B}-{\text{Al}}_2{\text{O}}_3{\text{Al}}_2{\text{O}}_3\text{(s)}+6\text{HCl(aq)}\to 2{\text{AlCl}}_3\text{(aq)}+3{\text{H}}_2\text{O(l)}{\text{Al}}_2{\text{O}}_3\text{(s)}+2\text{NaOH(aq)}\to 2{\text{NaAlO}}_2\text{(aq)}+{\text{H}}_2\text{O(l)}$