Question

Chemical formula of rust is 

1. Al₂O₃.nH₂O
2. Fe₂O₃.nH₂O
3. MgO
4. CaO

Answer 1

Correct Answer - Option 2 : Fe₂O₃.nH₂O

The correct answer is ​Fe2O3​.nH2O

CONCEPT:

• Iron objects when kept exposed to air develop a red coating on their surface. This is known as rusting of iron.

EXPLANATION:

• Iron exposed to air reacts with the oxygen and moisture in the air and forms hydrated iron oxide (Fe₂O₃.nH₂O).
• This iron oxide coating formed on the surface is known as rust.
• This is a chemical change.
• Rusting can destroy iron objects.
• Galvanization is the process used to prevent rusting.
• Galvanization is a metal coating process in which a ferrous part is coated with a thin layer of zinc. This avoids the direct contact of iron with air and thereby prevents rusting.