Will glucose give a positive Benedict test?

This means that glucose will give a positive test with Benedicts' reagent, Fehlings solution, or the Tollens test, and the aldehyde will be oxidized to a carboxylic acid.Sep 12, 2017

Is glucose positive in Benedict Test?

Water plus Benedict's reagent is a negative control for the sugar test. It demonstrates a negative test result (no sugar present). See tube 1 above. Glucose plus Benedict's reagent is a positive control for the sugar test.

Which sugar gives Benedict test positive?

The reducing sugars that show positive results with benedict's solution are glucose, fructose, maltose etc. The correct option is D i.e. sucrose. Additional Information: Sucrose is a disaccharide composed of two monosaccharide molecules that are glucose and fructose.

Does lactose give a positive Benedict test?

Lactose, D-ribose, and D-glyceraldehyde would give a positive Benedict's test. To be a reducing sugar, a disaccharide must contain an anomeric carbon atom that can open up to form an aldehyde functional group, as shown in this disaccharide (answers will vary).

Does galactose give a positive Benedict test?

In short, any sugar* (*mono- or disaccharide) with a hemiacetal will also give a positive test, since these sugars are in equilibrium with an open-chain aldehyde. So if the blood/urine contains common monosaccharides like mannose, galactose, or fructose, these will deliver a positive test.

Which sugar does not give a positive Benedict test?

Sucrose Sucrose (table sugar) contains two sugars (fructose and glucose) joined by their glycosidic bond in such a way as to prevent the glucose undergoing isomerization to an aldehyde, or fructose to alpha-hydroxy-ketone form. Sucrose is thus a non-reducing sugar which does not react with Benedict's reagent.

Why does glucose and lactose give a positive Benedict test?

Answer. The common disaccharides lactose and maltose are directly detected by Benedict's reagent because each contains a glucose with a free reducing aldehyde moiety after isomerization. Sucrose is thus a non-reducing sugar which does not react with Benedict's reagent.

Which sugar does not give Benedict Test?

Sucrose contains two sugars (fructose and glucose) joined by their glycosidic bond in such a way as to prevent the glucose isomerizing to aldehyde, or the fructose to α-hydroxy-ketone form. Sucrose is thus a non-reducing sugar, which does not react with Benedict's reagent.

Which carbohydrates give a positive Benedict test?

Because both the Tollens' and Benedict's reagents are basic solutions, ketoses (such as fructose) also give positive tests due to an equilibrium that exists between ketoses and aldoses in a reaction known as tautomerism.