Question

what is the nature of rust? is it soft and dull or something other

Answer 1

Dear student!

The rusting occurs because of the reaction of iron or other corrosive metals with atmospheric oxygen and moisture which forms iron (III) hydrated oxides and iron (III) oxide-hydroxide.

The rusting process occurs in presence of water and atmospheric oxygen as:

4Fe + n H₂O + 3O ₂$\to$ 2 Fe₂O_{3 .}nH₂O

Actually, this is a chemical change that occurs over the metal surface to prevent it from further corrosion, as the iron oxide makes a layer or coating over the rest surface which saves iron from further corrosion.Rust is a hard solid substance and it has dull appearance.