In acidic medium, the balanced redox reaction for MnO₄⁻ + Fe²⁺ → Mn²⁺ + Fe³⁺ is:

Correct option is B

The correct answer is (b) MnO₄⁻ + 5Fe²⁺ + 8H⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O

Explanation:

• In acidic medium, the redox reaction between permanganate ions (MnO₄⁻) and iron(II) ions (Fe²⁺) proceeds as follows:
• The MnO₄⁻ ion is reduced to Mn²⁺, and the Fe²⁺ is oxidized to Fe³⁺.
• In acidic medium, hydrogen ions (H⁺) are involved to balance the equation.
• The balanced equation can be written as:
  MnO₄⁻ + 5Fe²⁺ + 8H⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O.
• This ensures mass and charge balance, with 5 electrons being transferred from iron(II) to permanganate.

Information Booster:

• Oxidation half-reaction:
  Fe²⁺ → Fe³⁺ + e⁻
• Reduction half-reaction:
  MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O
• The electrons are balanced by combining the two half-reactions, leading to the overall reaction shown in option (b).

Additional Knowledge:
(a) MnO₄⁻ + 3Fe²⁺ + 2H⁺ → MnO₂ + Fe³⁺ + H₂O:

• This equation is incorrect as it doesn't balance the charge or mass properly. Additionally, MnO₂ is not the correct product in acidic medium; Mn²⁺ should be formed instead.

(c) MnO₄⁻ + 2Fe²⁺ + H₂O → Mn²⁺ + Fe³⁺:

• This is not the correct balanced equation, as it doesn't account for the necessary hydrogen ions in an acidic medium, nor does it correctly balance the number of electrons.

(d) MnO₄⁻ + Fe²⁺ → MnO₂ + Fe³⁺:

• This equation is incorrect because it doesn't involve the acidic medium and produces MnO₂ instead of Mn²⁺. This would be true in a basic medium, not acidic.