Question

Karen is working with an unknown organic substance. She mixes a sample of the substance with Benedict's solution and heats it. The mixture changes from blue to a orange/red color. Based on the test results, Karen can conclude that the unknown substance is a

Answer 1

It is a reducing sugar.

Benedict's reagent is a chemical reagent named after American chemist Stanley Rossiter Benedict. It is a complex mixture of sodium carbonate, sodium citrate and copper(II) sulphate pentahydrate. It is often used in place of Fehling's solution to detect the presence of reducing sugars.

Answer 2

Based on the test results, the organic substance that Karen is testing is glucose.

When glucose is heated with Benedict's solution, it forms an orange-red or brick red precipitate that is indicative of the presence of aldehyde group.

Since glucose gives a positive test, it can be used to test glucose presence in urine, and confirm the a patient has diabetes.