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What does Tollens reagent Fehlings solution 2 4-Dinitrophenylhydrazine and Benedicts solution test for and what are the results?
Wiki User
∙ 13y ago
Brady's reagent (2,4-DNP) forms a orange precipitate for all carbonyl compounds (C=O functional group), both aldehydes (primary) and ketones (secondary). However, recrystalisation of the orange precipitate gives characteristic melting points of the crystal for each carbonyl compound (therefore the presence of an orange precipitate indicates a carbonyl compound and the melting point of the crystallised precipitate indicates the type of carbonyl compound; aldehyde or ketone).
Tollen's reagent (diamminesilver nitrate solution) is reduced and forms a silver mirror when heated with an aldehyde. It distinguishes between aldehydes and ketones as ketones do not react (no silver mirror formed) as they can not be oxidised further.
Fehling's solution (copper II ions in sodium hydroxide) is reduced from a blue solution (Cu II ions) to a brick red precipitate (Cu I ions) when heated in the presence of an aldehyde. Ketones do not react as they can not be oxidised further.
The Benedict's test is used in organic chemistry to distinguish between reducing sugars (brick red precipitate formed) and non-reducing sugars (no reaction).
Wiki User
∙ 13y ago
Tollens reagent tests for aldehydes, giving a silver mirror when positive. Fehling's solution tests for aldehydes, forming a brick-red precipitate. 2,4-Dinitrophenylhydrazine tests for carbonyl compounds, producing an orange precipitate known as a "2,4-DNP derivative." Benedict's solution tests for reducing sugars, forming a brick-red precipitate in the presence of reducing sugars.
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What compound can be oxidized by both Benedicts solution and Tollens reagent?
A reducing sugar such as glucose can be oxidized by both Benedicts solution and Tollens reagent to form a colored precipitate. This reaction is used to test for the presence of reducing sugars in a solution.
Does the tollens test deal with alkenes?
No, the Tollens test is used to detect aldehydes, not alkenes. Alkenes do not react with Tollens' reagent.
Is fructose gives positive test with tollens reagent?
Fructose does not give a positive test with Tollens' reagent because it is a reducing sugar that does not have a free aldehyde group capable of reducing the Tollens' reagent. Tollens' reagent is typically used to detect the presence of aldehydes but may not react with fructose due to its ketone functional group.
How do you prepare tollen reagent?
To prepare Tollens reagent, mix aqueous silver nitrate with ammonia solution until a precipitate forms. Then add sodium hydroxide solution to redissolve the precipitate and form the final reagent. It is used to test for the presence of aldehydes in a reaction.
What happen when you react sugar like glucose and fructose with tollen' s reagent and the Fehlings solution?
When glucose reacts with Tollen's reagent, it forms a silver mirror precipitate indicating the presence of an aldehyde functional group. Fructose, on the other hand, does not produce a silver mirror with Tollen's reagent because it is a ketose sugar. When either glucose or fructose reacts with Fehling's solution, they both reduce the copper ions in the solution to form a red precipitate of copper(I) oxide, indicating the presence of reducing sugar.
What compound can be oxidized by both Benedicts solution and Tollens reagent?
A reducing sugar such as glucose can be oxidized by both Benedicts solution and Tollens reagent to form a colored precipitate. This reaction is used to test for the presence of reducing sugars in a solution.
Why ketone do not react with Fehlings solution and Tollens reagent?
Ketones do not react with Fehling's solution or Tollens' reagent because they lack the free aldehyde group necessary for these reactions to occur. Both Fehling's solution and Tollens' reagent depend on the presence of the aldehyde group to participate in redox reactions that lead to the formation of a colored precipitate. Without this aldehyde group, ketones do not undergo these reactions.
What happens to aldehyde when it reacts with fehlings solution or tollens solution?
Aldehyde are oxidised to the corresponding carbonic acid by F.'s or T.'s agents. Ketone can not be oxidised.
What is the difference between fehling's solution and tollens reagent?
Fehling's solution is used to test for the presence of reducing sugars, while Tollens reagent is used to test for the presence of aldehydes. Fehling's solution contains cupric ions, while Tollens reagent contains silver ions. When a reducing sugar reacts with Fehling's solution, a brick-red precipitate forms, while with Tollens reagent, silver ions are reduced to form a silver mirror on the test tube.
explain using sample equation, the application of benedicts tollens and fehlings test in hospital?
Benedict's test and Fehling's test are both used to detect reducing sugars in body fluids (e.g. urine) that may indicate conditions like diabetes. In the tests, a reducing sugar like glucose reacts with the reagents to form a colored precipitate, indicating a positive result. This can help healthcare professionals diagnose and monitor patients with sugar metabolism disorders.
Explain using sample equationthe application of benedicts tollens and fehlings test in hospital?
Benedict's test is used to detect the presence of reducing sugars in the patient's urine, which may be indicative of conditions like diabetes. Fehling's test is used to detect reducing sugars in the blood, which can help in diagnosing conditions like diabetic ketoacidosis. Both tests provide valuable information for healthcare professionals to evaluate a patient's carbohydrate metabolism and diagnose related conditions.
What is the reaction of acetone and tollens reagent?
Acetone does not react with Tollens' reagent (ammoniacal silver nitrate solution) because it does not contain an aldehyde group, which is necessary for the Tollens' test to occur. Tollens' reagent reacts with aldehydes to produce a silver mirror on the inner surface of the test tube.
What are the components of tollens reagent?
Tollens reagent is composed of silver nitrate solution, ammonia solution, and sodium hydroxide solution. Silver ions in the solution are reduced to silver metal, forming a silver mirror on the inside of a test tube when aldehydes are present.
Is vanillin positive in tollens test?
No, vanillin is not positive in the Tollens test. The test is used to detect the presence of aldehydes, while vanillin is actually an aldehyde derivative. It does not react with Tollens reagent as traditional aldehydes would.
When was Bernhard Tollens born?
Bernhard Tollens was born on 1841-07-30.
When did Bernhard Tollens die?
Bernhard Tollens died on 1918-01-31.
When did Hendrik Tollens die?
Hendrik Tollens died on 1856-10-21.
