Question

Aluminium reacts with $HCl$ to form $H_2$gas, but do not react with $HN{O}_3$, why?

• A. $Al$ with $HN{O}_3$ forms $A{l}_2{O}_3$ which is passive for further reaction
• B. $Al$ with $HN{O}_3$ forms $A{l}_2{O}_7$ which is passive for further reaction
• C. $Al$ with $HN{O}_3$ forms $A{l}_2{O}_4$ which is passive for further reaction
• D. $Al$ with $HN{O}_3$ forms $A{l}_3{O}_2$ which is passive for further reaction

Answer 1

The correct option is A $Al$ with $HN{O}_3$ forms $A{l}_2{O}_3$ which is passive for further reaction

When $Al$ reacts with $HCl$ it forms $AlC{l}_3$ which is soluble but when it reacts with $HN{O}_3$ its upper layer gets oxidised in to $A{l}_2{O}_3$ which is passive for further reaction with $HN{O}_3$ as $A{l}_2{O}_3$ is highly stable metal oxide.