Question

Which of the following is not a constituent of bleaching solution ?

• A. Hydrogen peroxide
• B. Sodium iodate
• C. Acetone
• D. Ammonium hydroxide

Hint:

Bleaching requires a chemical reaction called Oxidation. Always look for strong oxidizers (like peroxides, permanganates, or iodates) as bleaches. Acetone and alcohol are just solvents/dehydrators.

Answer 1

The Correct Option is C

Step 1: Concept:
This question tests knowledge of chemical reagents used in histopathology laboratories, specifically focusing on the composition of solutions used for histological tissue bleaching (such as melanin depigmentation).

Step 2: Step-by-step Explanation:

• In histopathology, highly pigmented tissues (like skin containing dense melanin) can obscure cellular details when stained. To fix this, technologists use bleaching solutions to oxidize and remove the pigment before applying routine stains like H&E.

• Hydrogen peroxide (A) is one of the most common, powerful oxidizing agents used globally as a primary bleaching agent in laboratories.

• Ammonium hydroxide (D) is frequently added in drops to the hydrogen peroxide solution. The strong alkaline environment accelerates the oxidative bleaching process significantly.

• Sodium iodate (B) is a strong oxidizing agent. While primarily known for chemically "ripening" hematoxylin stains by oxidizing it to hematein, oxidizing agents by their chemical nature have bleaching properties.

• Acetone (C) is a simple, highly volatile organic ketone. In the lab, it acts purely as a non-polar solvent, a dehydrating agent, or a rapid fixative. It possesses absolutely zero oxidative properties and therefore cannot chemically bleach pigments.

Step 3: Final Answer:
Acetone is not a constituent of bleaching solutions.