Which of the following is the formula for rust?
AFe₂OH·H₂O
BFeO₃·H₂O
CFe₂O·H₂O
DFe₂O₃·H₂O
Answer & Solution
Correct answer: D. Fe₂O₃·H₂O
1. Rust forms when iron reacts with oxygen and moisture.
2. It is hydrated iron(III) oxide.
3. Its formula is Fe₂O₃·H₂O.
_Source: RRB Group D CEN-02/2018 PYQ, Q.96 (rust)._