Question

Aluminium metal becomes passive in

• A. cone. $HN{O}_3$
• B. dil. $H_{2}S{O}_4$
• C. very dil. $HN{O}_3$
• D. cone. $H_{2}S{O}_4$

Answer 1

Answer: (A)

Aluminium metal becomes passive in concentrated $\text{HN}{\text{O}}_{\text{3}}$ due to the formation of an oxide layer over its surface.