Which of the following is NOT a step in balancing redox reactions in acidic media?

• A. Add OH- to balance hydrogen atoms.
• B. Add H2O to balance oxygen atoms.
• C. Balance the charges by adding electrons.
• D. Add H+ to balance hydrogen atoms.

Answer: (A)

Verified step by step guidance

1. Understand that balancing redox reactions in acidic media involves specific steps to ensure both mass and charge are balanced.
2. Recall that in acidic media, oxygen atoms are balanced by adding water molecules (\(\mathrm{H_2O}\)) to the side deficient in oxygen.
3. Hydrogen atoms are balanced by adding hydrogen ions (\(\mathrm{H^+}\)), not hydroxide ions (\(\mathrm{OH^-}\)), because the solution is acidic.
4. Balance the charges on both sides of the half-reactions by adding electrons (\(\mathrm{e^-}\)) as needed.
5. Recognize that adding hydroxide ions (\(\mathrm{OH^-}\)) is a step used in basic media, not acidic media, so it is NOT a step in balancing redox reactions in acidic media.