Fehling is a term commonly associated with Fehling's solution, a chemical solution used to detect the presence of reducing sugars, particularly in organic compounds. Fehling's solution consists of two separate solutions: Fehling solution A and Fehling solution B.
Fehling solution A is composed of copper(II) sulfate (CuSO4) dissolved in water, while Fehling solution B is a mixture of sodium potassium tartrate (also known as Rochelle salt) and sodium hydroxide (NaOH). When these two solutions are combined, a reaction takes place, resulting in the reduction of copper(II) ions to copper(I) ions.
The reduction reaction occurs when a reducing sugar, such as glucose or fructose, is present in the solution. The reducing sugar acts as a reducing agent, capable of donating electrons to the copper(II) ions, causing their reduction. This reduction reaction results in the formation of a brick-red precipitate of copper(I) oxide (Cu2O).
The Fehling test is commonly used as a qualitative test for the presence of reducing sugars in various substances, typically in the fields of chemistry and biochemistry. It is particularly useful in analyzing complex organic compounds and is often employed in laboratory settings as a means of identifying the presence of sugars in unknown samples.
Overall, Fehling, and Fehling's solution more specifically, is a chemical test commonly employed to identify the presence of reducing sugars in organic compounds by the formation of a characteristic precipitate.
