Q21 / 90 · JEE Main 2023 (11 Apr Shift 2) · Chemistry

Number of compounds from the following which will not produce orange red precipitate with Benedict solution is........
Glucose, maltose, sucrose, ribose,2-deoxyribose, amylose, lactose

Correct answer: 2

Solution

Except sucrose and amylose all others, give orange red precipitate with Benedict solution.
Sucrose is a non-reducing disaccharide composed of glucose and fructose. It does not have a free aldehyde or ketone group and, therefore, cannot undergo oxidation and reduce the Benedict's reagent. As a result, sucrose will not produce an orange-red precipitate with the Benedict's solution.

Amylose is a polysaccharide composed of multiple glucose units linked together. While glucose, a monosaccharide, is a reducing sugar, the glycosidic bonds in amylose prevent the free aldehyde or ketone group from being available for oxidation. As a result, amylose, as a part of starch, does not give a positive Benedict's test and will not produce an orange-red precipitate.

Hence, the correct answer is 2.

Relevant Questions