Answer:
Fe → Fe⁺³ + 3e⁻
Step-by-step explanation:
The oxidation half reaction for iron is:
Fe → Fe⁺³ + 3e⁻
Other options are incorrect because,
A) 3e⁻ + Fe → Fe³⁺
This is incorrect because when three electrons are gained by any atom it will gain negative three charge not positive.
C) 6e⁻ + 2Fe → 2Fe³⁺
This is incorrect because when six electrons are gained by any atom it will gain negative six charge not positive.
d) Fe → 2Fe³⁺ + 6e⁻
Its also incorrect because iron atoms are not balanced on both side of equation.