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Benedict's Test for Glucose

Glucose is heated with Benedict's reagent to form a brick red precipitate.

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Narrative
Benedict's reagent is a solution of copper sulfate, sodium hydroxide, and tartaric acid. Aqueous glucose is mixed with Benedict's reagent and heated. The reaction reduces the blue copper (II) ion to form a brick red precipitate of copper (I) oxide. Because of this, glucose is classified as a reducing sugar.

Discussion
Aqueous glucose is mixed with Benedict's reagent, a solution of copper sulfate, sodium hydroxide, and tartaric acid. The mixture is heated. Carbohydrates which react with Benedict's reagent to reduce the blue copper (II) ion to form a brick red precipitate of copper (I) oxide are classified as reducing sugars.


       

Results of Benedict's Test with Glucose, Sucrose, and Fructose