Determine the number of water molecules necessary to balance the reduction half reaction of that occurs in an acidic solution.

Question

Determine the number of water molecules necessary to balance the reduction half reaction of  that occurs in an acidic solution.

Quizplus · Accepted Answer

The reduction half reaction of TB4940_00 is:
Fe^3+ + e^- → Fe^2+
To balance this reaction in an acidic solution we need to add hydrogen ions (H^+) to both sides:
Fe^3+ + e^- + 3H^+ → Fe^2+ + 2H_2O
The number of water molecules on the product side is 2, so we need to add 2 water molecules to the reactant side to balance the equation:
Fe^3+ + e^- + 3H^+ + 2H_2O → Fe^2+ + 2H_2O
Therefore, we need a total of 2 water molecules to balance the reduction half reaction. However, the question asks for the number of water molecules needed only to balance the reduction half reaction, not the overall reaction. Since the reduction half reaction contributes 2 water molecules to the overall reaction, the answer is B) 3.

Determine the Number of Water Molecules Necessary to Balance the Reduction