When Fe is rusted, the final product formed has Fe in which of the following state?

+3 state

The correct answer is option 2. +3 state.

When iron (Fe) rusts, it undergoes oxidation, which involves the loss of electrons. In the rusting process, iron reacts with oxygen (O₂) and water (H₂O) to form iron oxide, commonly known as rust. The chemical equation for the rusting of iron can be represented as:

\(4 \text{Fe} + 3 \text{O}_2 + 6 \text{H}_2\text{O} \rightarrow 4 \text{Fe}(\text{OH})_3 \)

In this reaction, iron atoms lose electrons to form iron ions, which then combine with hydroxide ions (\( \text{OH}^- \)) from water to form iron hydroxide (\( \text{Fe}(\text{OH})_3 \)). Iron hydroxide further oxidizes and dehydrates to form hydrated iron(III) oxide or rust (\( \text{Fe}_2\text{O}_3 \cdot x\text{H}_2\text{O} \)).

The oxidation state of iron in rust is primarily +3. In the chemical formula for rust, \( \text{Fe}_2\text{O}_3 \), each iron atom is in the +3 oxidation state. This indicates that each iron atom has lost three electrons during the rusting process, making it an iron(III) ion.

Therefore, when iron rusts, the final product formed predominantly contains iron in the +3 oxidation state.

In summary, the rust formed when iron rusts contains iron primarily in the +3 oxidation state, making the correct explanation +3 state.