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Why sucrose does not give a positive Benedict's test but hydrolyzed sucrose does give a positive beneditcts test?
Wiki User
∙ 9y ago
Sucrose is formed from glucose and fructose.Sucrose is formed from glucose and fructose. Glucose and fructose gives positive test for benedict becuz both of them are reducing sugars whereas sucrose is not a reducing sugar so it gives negative test for benedict.
On prolonged heating,sucrose will form glucose and fructose (reducing sugars)which ultimately gives a positive result .
Wiki User
∙ 9y ago
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After hydrolysis did sucrose give a positive test with fehlings test why orwhy not?
After hydrolysis sucrose did give a positive test. It reduces sugar that has hemiketal and hemiaetal in it.
Why does fructose give a positive Benedicts test?
Benedict's test detects the presense of the aldehyde group. Fructose is a ketose rather than an aldose, but it's converted to glucose or mannose (both of which are aldoses) by the base in Benedict's reagent. All monosaccharides give a positive Benedict's test because they're all either aldoses or alpha-hydroxy ketoses that get transformed into aldoses. Sucrose does not, because while it contains fructose and glucose, both of which do test postive, the saccharides in sucrose are "locked" into hemiacetal form and cannot undergo ring opening to expose an aldehyde group. (It's a very weak lock; dilute acid ... like, say, lemon juice ... will hydrolyse the saccharide linkage and allow the hemiacetal rings to open.)
Why can benzoic acid be dissolved in alcohol while sugar cannot?
Sugar (or Sucrose) molecules are polar. They have a slight positive end and a slightly negative end. Water molecules have the same property. For this reason, the positive end of a sucrose molecule will be attracted to the negative end of a water molecule and dissolve.Alcohols are non-polar and are equally charged on all sides. The charged ends of the sucrose have nothing to be attracted to except other SUCROSE molecules, therefore they will not dissolve.However benzoic acid is also a polar molecule, but through heat (200 degress F) can bond with alcohol and create a solution...
What is the odor of sucrose?
Sucrose has no odor.
Is sucrose magnetic?
Sucrose is not magnetic.
What is sucrose changed into when hydrolyzed?
When hydrolyzed, sucrose is change into glucose and fructose.
Would sucrose test positive or negative with benedicts reagent?
No, surcose is a disaccharide without a hemiacetal group
What sugar might be present in a sweet tasting food that tests negative with the Benedicts reagent?
Sucrose. Sucrose is a disaccharide therefore does not have free electrons in the sugar to react with the Benedict reagent. Glucose has free electrons therefore shows positive with the Benedict reagent.
What does sucrose yield when digested?
Sucrose is broken down into glucose and fructose by the enzyme sucrase.
Why does sucrose not react to Benedicts when glucose and fructose its components do?
Fructose and glucose are joined by their glycosidic bond in such a way as to prevent the glucose isomerizing to aldehyde, or the fructose to alpha-hydroxy-ketone form. This stops it reacting to Benidict's reagent. However sucrose indirectly produces a positive result with Benedict's reagent if heated with dilute hydrochloric acid prior to the test, although after this treatment it is no longer sucrose. ;-)
Would glucose solution produce a positive Benedicts test?
No, Benedicts reagent will show positive results if the carbohydrate is a reducing sugar. You will know if it is positive if the sample will turn from blue to green then to orange when you are cooling the solution, which is the last step when you are performing the benedicts test for carbohydrates.
What results from the action of sucrase on sucrose?
A molecule of common table sugar, sucrose, can be hydrolyzed into its two main molecular components by the enzymatic action of sucrase. Following hydrolysis, the resulting fragments are fructose and glucose.
How does Benedicts test indicate hydrolysis of sucrose and starch?
Benedict 's solution contains Copper , which can accept electrons from reducing sugars and consequently change color. A positive Benedict's sugar test will produce an orange to brick-red color. Reducing sugars have either a free aldehyde functional group or a free ketone functional group as part of their molecular structure; starches and other polysaccharides lack these functional groups . If Benedict's test changes color ( pos. reaction ) polysaccharides must be hydrolyzed.
After hydrolysis did sucrose give a positive test with fehlings test why orwhy not?
After hydrolysis sucrose did give a positive test. It reduces sugar that has hemiketal and hemiaetal in it.
In this experiment there was a positive sucrose uptake Sucrose probably entered the cells by what means?
it's active transport.
Each sucrose molecule is hydrolyzed in the small intestine to form one molecule of what?
The sucrose molecules are broken down in the molecules of glucose which is the simplest form od the saccharides. The sucrose in the body is not readily metabolized but it has to be broken down into simpler form of molecules. The glucose is easily metabolized int he body.
Why is glucose converted to sucrose before it can be transported away from the leaves?
Because the bonds formed within sucrose are not easily hydrolyzed.
