Answer:
Explanation:
Oxygen gas and water must be present for iron to rust.
A region of the metal’s surface serves as the anode, where oxidation
occurs:
Fe(s) → Fe²⁺ (aq) + 2 e⁻
The electrons given up by iron reduce atmospheric oxygen to water at the cathode, which is another region of the same metal’s surface:
O₂ (g) + 4H⁺ (aq) + 4 e⁻ → 2 H₂O (l)
The overall redox reaction is:
2 Fe(s) + O₂(g) → 4H⁺(aq) + 2Fe²⁺ (aq) + 2 H₂O(l)
The Fe²⁺ ions formed at the anode are further oxidized by oxygen:
4 Fe²⁺ (aq) + O₂(g) 1 (4 + 2x) H₂O (l) → 2 Fe₂O₃ . xH₂O(s) + 8 H⁺(aq)
This hydrated form of iron(III) oxide is known as rust. The amount of water associated with the iron oxide varies, so we represent the formula as 2 Fe₂O₃ . xH₂O.
I believe the correct answer among the choices listed above is the last option. Plants seemed to evolve in the order of bryophytes, gymnosperms,angiosperms. Bryophytes are mosses that lack vascular tissue. Gymnisoerm do not have seeds but have vascular tissue. Angiosperms have flowers and seeds for mating.
