Acid cleaning solutions contain which compound in concentrated sulfuric acid?

• A. Potassium dichromate in concentrated sulfuric acid
• B. Potassium permanganate in concentrated sulfuric acid
• C. Hydrochloric acid
• D. Sodium hydroxide

Answer: (A)

The key idea is that acid cleaning solutions use chromic acid, which is formed in situ by mixing potassium dichromate with concentrated sulfuric acid. In strongly acidic conditions, the dichromate ion is reduced to chromic acid (H2CrO4), a very powerful oxidizer that efficiently removes organic residues from glassware and metal surfaces. That makes the combination of potassium dichromate with concentrated sulfuric acid the correct description of the cleaning reagent.

The other options don’t fit because they involve different substances that aren’t used to generate chromic acid in this cleaning context. Hydrochloric acid is a strong acid but not an oxidizing cleaning agent produced this way, sodium hydroxide is a base, and a mixture of potassium permanganate with sulfuric acid would create a different oxidative system not characteristic of the traditional chromic acid cleaner.