Question

Give three ways in which the metal than iron,but suffers less corrosion.Why?

(b) Explain and give reasons why aluminium vessels should not be cleaned with powders containing alkalis.

Answer 1

(a)
Aluminium forms white colour oxide on exposure to the atmosphere. This white colour oxide prevents it from further corrosion whereas iron reacts with air to form hydrated oxide called rust. So, iron undergoes corrosion to greater extent.
(b) Aluminium vessels should not be cleaned with powders containing alkalis because it results in the formation of meta aluminates and hydrogen.
2Al + 2NaOH + 2H₂O → 2NaAlO₂ + 3H₂