answersLogoWhite

0


Best Answer

All aldehydes give a positive result with Fehling's test. All ketones give negative results.

User Avatar

Wiki User

13y ago
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: Which aldehyde do not give fhelings test?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Continue Learning about Natural Sciences

What should you know about gluctose and fructose to be considered as different compounds?

Glucose belongs to aldoses group i.e it has a aldehyde group in it.. whereas fructose belongs to ketoses group i.e ketonic group is present. so glucose gives +ve test for aldehyde group test & one which doesn't give is fructose.


What is an aldehyde oxidase?

An aldehyde oxidase is an enzyme which catalyzes the oxidation of an aldehyde to a carboxylic acid.


How do you convert a diol into an aldehyde?

How do you convert a diol into an aldehyde?


What is an amino aldehyde?

An amino aldehyde is an organic compound containing both an amino and an aliphatic aldehyde functional group.


what is the equation for this aldehyde plus acidified potassium permanganate aldehyde plus Tollen's reagent aldehyde plus NaOH Cannaizarro's reaction aldehyde plus Fehling's rgt aldehyde plus Sodium H?

the equation for this are? aldehyde + acidified potassium permanganate RCHO + 2KMnO4 + H2SO4 → RCOOH + K2SO4 + 2MnO2 ↓+ H20 aldehyde + Tollen's reagent RCHO + 2AgNO3 + 2NH4OH → RCOOH + 2Ag↓ + 2NH4NO3 +H2O aldehyde+ Fehling's reagent RCHO + 2CuSO4 + 4NaOH →RCOOH + Cu2O↓+ 2Na2SO4 + 2H2O THAT's ALL I KNOW aldehyde + Sodium Hydrogen Sulfite

Related questions

What is the function of Fehling's test?

Fehling's test is used to differentiate between aldehyde and ketones group. An aldehyde group will react with Fehling's reagent to give cuprous oxide resulting in a red precipitate. A Ketone group will not react with Fehling's reagent.


What substances give a positive tollens test?

When adding the aldehyde or ketone to Tollens' reagent, the test tube is put in a warm water bath. If the reactant under test is an aldehyde, Tollens' test results in a silver mirror. If the reactant is a ketone, it will not react because a ketone cannot be oxidized easily. A ketone has no available hydrogen atom on the carbonyl carbon that can be oxidized - unlike an aldehyde, which has this hydrogen atom.


Does vanillin gives iodoform test?

No because vanillin is phenolic aldehyde (only acetaldehyde give idoform among all ketones)


What test is used to show the reducing property of an aldehyde and a ketone?

tollen's test, fehling's test, iodoform test


What should you know about gluctose and fructose to be considered as different compounds?

Glucose belongs to aldoses group i.e it has a aldehyde group in it.. whereas fructose belongs to ketoses group i.e ketonic group is present. so glucose gives +ve test for aldehyde group test & one which doesn't give is fructose.


Why pyrrole-2-aldehyde does not respond to tollens reagent?

Pyrrole-2-aldehyde does not respond to Tollens reagent because it is not a reducing sugar. Tollens reagent (silver nitrate) is used to test for the presence of aldehyde groups, which are commonly found in reducing sugars. Reducing sugars contain aldehyde groups and are capable of donating electrons to Tollens reagent, forming a silver mirror on the test tube wall. Pyrrole-2-aldehyde does not contain aldehyde groups, and therefore is not a reducing sugar. As a result, it does not react with Tollens reagent.


Why does sucrose solution give a negative test with tollen's test?

A positive Tollen's test is given by compounds that have a free aldehyde or ketone functional group. Sucrose is a disaccharide composed of the monosaccharides glucose and fructose. In sucrose, the components glucose and fructose are linked via an ether bond between C1 (carbon with aldehyde group) on the glucosyl subunit and C2 (carbon with ketone group) on the fructosyl unit. The bond is called a glycosidic linkage. In other words, in sucrose there is no free aldehyde or ketone functional group. Hence sucrose will not answer Tollen's test.


What is the principle of aldehyde test for proteins?

formaldehyde reacts with oxidised indole ring to give coloured complex .mercuric sulphate in sulphuric acid acts as the oxidising agent


Is vanillin positive in DNPH test?

Yes, it contains carbonyl functional group- aldehyde! :)


Why does the formic acid give positive test with Tollens reagent?

The formic acid is special because doesn't contain an alkyl group but only an atom of hydrogen; so resembles to an aldehyde.


Is cinnamaldehyde an aldehyde or ketone?

cinnamaldehyde is a aldehyde hence cinnam(aldehyde)


Why is fructose oxidized by fehling's reagent even though it is a ketose?

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.