If a sample has no reducing sugar, Benedict's test colour remains?

• A. Brick red
• B. Blue
• C. Green
• D. Orange

Answer: (B)

The test relies on reducing sugars being able to donate electrons to the copper(II) ions in Benedict’s reagent when heated. If a reducing sugar is present, the blue solution is reduced and changes color—from blue to green, then yellow, orange, or brick red as the amount of sugar increases. If there are no reducing sugars, nothing is reduced and the solution stays blue. So, for a sample with no reducing sugar, the Benedict’s test colour remains blue. The other colours indicate increasing amounts of reducing sugar, which aren’t present here.