Give reasons:
- Aluminium is a reactive metal but is still used for packing food articles.
- Red litmus paper turns blue when touched with aqueous solution of magnesium oxide.
Answer:
- On exposure to air, aluminium forms a hard protective layer of aluminium oxide (A1203) which prevent further oxidation.
- Magnesium oxide is an oxide of a metal, so, it is basic in nature. Due to its basic character it turns red litmus paper blue when touched with its aqueous solution.