A liquid solution of copper sulfate and potassium tartrate and sodium hydroxide that is used to test for sugar in the urine; solution turns reddish when sugar is present WordNet 3.0 & Open English WordNet

In organic chemistry, Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone functional groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' reagent test. Wikipedia

reagent used for analysis of solution Wikidata

An alkaline solution of copper sulphate which changes from blue to red in the presence of an aldehyde or a reducing sugar. Wiktionary

An alkaline solution. Wiktionary (translation)