The reddish–brown rust on ion roofing sheets consists of?

A. Fe³+ (H2O)6
B. FeO.H2O
C. Fe2O3.3H2O
D. Fe3O4.2H2O

Correct Answer:

Option C – Fe2O3.3H2O

Explanation

Iron [Fe] reacts with H2 in the presence of oxygen to form a rust.

4Fe + 3O2 → 2Fe2O3

Fe2O3 + H2O → Fe2O3.3H2O