What functional group present in carbohydrate molecule produces a positive reaction with benedicts reagent?

Aldehyde group

Explanation:

Benedict's Test:

Benedict's test detects the presence of simple carbohydrates such as monosaccharides and disaccharides in a sample. A Benedict's test is positive for reducing sugars that contain a free aldehyde or ketone group. When reducing sugars are heated in the presence of an alkali, they form enediols that are powerful reducing agents. A positive Benedict's test is indicated by an orange/brick-red colour.