What is the reaction of iodine when Benedict's test is positive?

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Benedict’s test is used to detect the presence of reducing sugars. All monosaccharides and some disaccharides such as lactose and maltose are called reducing sugars. When Benedict’s test is positive, an orange-red precipitate forms when the Benedict’s reagent is added to a solution contain reducing sugar.

The iodine test is a chemical test for starch. When iodine solution which is red is added to starch it turns blue/black in colour.

If according to your question, the Benedict’s test is positive, it implies that the solution contains a reducing sugar, in which case an orange-red precipitate forms when the Benedict’s reagent is added. Iodine does not react with reducing sugars and so when iodine (which is red) is added to such a solution, no colour change will be observed unless starch is present, in which case a blue/black colour change gives away the presence of starch. See the table at the end of this article.

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