Which of the following can be used as a primary standard in redox titrations?

The correct answer is KMnO₄.

Key Points

• KMnO₄ (Potassium permanganate) is a widely used primary standard in redox titrations due to its stability and known concentration.
• It acts as a strong oxidizing agent, which allows it to effectively titrate reducing agents.
• KMnO₄ can be standardized against a primary standard such as oxalic acid (H₂C₂O₄), ensuring precise concentrations.
• It is used in various applications including water treatment and in the determination of iron content in solutions.

Additional Information

• Redox Titration:
  • Redox titrations involve the transfer of electrons between the analyte and titrant, where one substance is oxidized and the other reduced.
  • Common redox titrants include KMnO₄, K₂Cr₂O₇ (Potassium dichromate), and iodine.
• KMnO₄ as a Primary Standard:
  • KMnO4 is a solid and is relatively stable, which makes it suitable for use as a primary standard in redox titrations.
  • It is typically used in acidic solutions for titrations involving reducing agents like oxalic acid, iron(II) salts, and hydrogen peroxide.
• Potassium Permanganate Properties:
  • KMnO₄ is deep purple in color and is commonly used to detect the presence of reducing agents in solutions.
  • It is also used as a disinfectant and in analytical chemistry to determine the concentration of certain compounds.