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Fehling's reagent contains CuO and NaOH. I think fructose could give a positive test because the OH- can react with the sugar and "move" the carbonyl around the carbon backbone, including to the terminal position, forming an aldehyde. If the aldehyde reacts with the CuO pretty quickly, then you may have created an "aldehyde sink" that could consume all of your fructose into the carboxylic acid.
What else can I help you with?
Is fructose classified as an aldose or a ketose?
Fructose is classified as a ketose.
Can Seliwanoff's test be used to distinguish sucrose from fructose?
Yes, fructose is a ketose, for which Seliwanoff's test is most sensitive. Sucrose is neither entirely a ketose nor an aldose, but is a mixture of both. It will react, but more slowly, producing a much lighter pinkish color.
What are examples of ketoses?
Fructose is a common example of a ketose, as it has a ketone group in its structure. Other examples include ribulose and dihydroxyacetone. These molecules have a carbonyl group (ketone) on the second carbon atom in the chain.
What are an aldose ketose pair?
An aldose-ketose pair refers to two monosaccharides that are isomers of each other, differing in the placement of a carbonyl group. In an aldose, the carbonyl group is located at the end of the carbon chain, while in a ketose, it is located within the carbon chain. For example, glucose is an aldose, while fructose is a ketose, and they are considered an aldose-ketose pair.
What monosaccharide is found in fruit?
fructoseThe monosaccharide responsible for sweet taste in fruit is fructose also known as levulose or fruit sugar.
Is fructose classified as an aldose or a ketose?
Fructose is classified as a ketose.
What happen when you react sugar like glucose and fructose with tollen' s reagent and the Fehlings solution?
Glucose oxidizes very quickly, and creates a silver mirror layer between the glucose solution and the Tollens' reagent. This is because of how the ketose reacts and reduces the silver molecules in Tollen's reagent.
Can Seliwanoff's test be used to distinguish sucrose from fructose?
Yes, fructose is a ketose, for which Seliwanoff's test is most sensitive. Sucrose is neither entirely a ketose nor an aldose, but is a mixture of both. It will react, but more slowly, producing a much lighter pinkish color.
How do you distinguish glucose and fructose?
Glucose is an aldose whereas fructose in a ketose. There is a simple qualitative test for distinguishing between D-Glucose and D-Fructose.
What is the result of the seliwanoff test if the solution contains both fructsoe and glucose?
the glucose would remain yellow which is the initial colour of the seliwanoff's reagent. the fructose however being a ketose forms a furfural because of the HCL present in the seliwanoff reagent and reacts with the resorcinol to give a red cherry or pink colour.
Can you name one or two monosaccharides made by plants?
Glucose and fructose are monosaccharides made by plants. Glucose is a simple aldose, fructose is a ketose.
What are examples of ketoses?
Fructose is a common example of a ketose, as it has a ketone group in its structure. Other examples include ribulose and dihydroxyacetone. These molecules have a carbonyl group (ketone) on the second carbon atom in the chain.
What are an aldose ketose pair?
An aldose-ketose pair refers to two monosaccharides that are isomers of each other, differing in the placement of a carbonyl group. In an aldose, the carbonyl group is located at the end of the carbon chain, while in a ketose, it is located within the carbon chain. For example, glucose is an aldose, while fructose is a ketose, and they are considered an aldose-ketose pair.
Why the majority said that sucrose is a ketose sugar?
The majority would be incorrect. Sucrose is not considered an aldose or a ketose, because it is a disaccharide made from glucose (an aldose) and fructose (a ketose). So, it has both properties within its structure. It is a non-reducing sugar.It is possible that many say sucrose is a ketose because sucrose will fail the Benedict's test, which is designed to detect aldoses.
What monosaccharide is found in fruit?
fructoseThe monosaccharide responsible for sweet taste in fruit is fructose also known as levulose or fruit sugar.
What test can be used to identify the presence of the fructose?
Seliwanoff's test is used to differentiate aldose [glucose] from ketose [fructose]. Seliwanoff's reagent is composed of resorcinol and HCl. When heated with concentrated hydrochloric acid, the polysaccharides and oligosaccharides hydrolyze to yield monosaccharides. Then, resorcinol reacts in the dehydrated ketose to form oxymethylfurfurol produce a deep cherry red color [red precipitate]. Aldoses produces a faint pink colored solution.
How do you prepare seliwanoffs reagent?
To prepare Seliwanoff's reagent, dissolve resorcinol in concentrated hydrochloric acid, then add a small amount of acetaldehyde. Mix well and dilute with water if needed. This reagent is used for differentiating between aldose and ketose sugars based on the color developed upon heating.
