Question

On heating glucose with Fehling's solution, we get a precipitate whose colour is _______.

• A. Yellow
• B. Red
• C. Black
• D. White

Answer 1

The correct option is B Red

On heating glucose with Fehling's solution, the presence of aldehyde functional group reduces the deep blue solution of copper (II) to a red precipitate of insoluble copper oxide. The test is commonly used for reducing sugars.
Glucose + Fehling solution ® Gluconic acid + ${Cu}_{2}O$ (red ppt)