Answer
Verified
444.9k+ views
Hint: Aldehydes which are present in the sugar gives positive Fehling’s test. Fehling’s test is a chemical test which is generally used to distinguish between aldehydes and ketone functional groups.
Complete answer:
The sugars which acts as a reducing agent in the alkaline solution is known as reducing sugars. Fehling’s solution is a mixture of copper sulphate, potassium sodium tartrate and sodium hydroxide. It is used to differentiate between the water soluble carbohydrates that are aldehydes and the ketonic functional group and acts as a test for the reducing sugars.
In the basic medium, fructose shows keto enol tautomerism and thus isomerizes to glucose due to which fructose gives a positive Fehling’s test. This is shown below:
\[D-fructoseenol\text{ intermediate}D-glu\cos e\]
Hence the correct answer is (A) i.e. Fructose given positive Fehling’s solution test is a true statement.
Additional information:
Fehling’s solution is prepared by mixing Fehling’s A and Fehling’s B. this solution acts as an oxidizing agent. Due to the presence of copper the solution gives blue color which on reaction with the aldehyde group turns the copper ions to copper oxide which appears as red precipitate.
The sugar having free aldehyde groups gets reduced but the one without the aldehyde group gives a negative test. The reaction involved is mentioned below:
$RCHO+2C{{u}^{2+}}+5O{{H}^{-}}\to RCO{{O}^{-}}+C{{u}_{2}}O+3{{H}_{2}}O$
Note:
The Fehling’s test is sensitive enough because 1 mg of glucose will be sufficient to produce the characteristic red color of the compound. This test is used to differentiate between the reducing sugars and non reducing sugars. And one more important point is that this test will turn out positive only when a free aldehyde group is present.
Complete answer:
The sugars which acts as a reducing agent in the alkaline solution is known as reducing sugars. Fehling’s solution is a mixture of copper sulphate, potassium sodium tartrate and sodium hydroxide. It is used to differentiate between the water soluble carbohydrates that are aldehydes and the ketonic functional group and acts as a test for the reducing sugars.
In the basic medium, fructose shows keto enol tautomerism and thus isomerizes to glucose due to which fructose gives a positive Fehling’s test. This is shown below:
\[D-fructoseenol\text{ intermediate}D-glu\cos e\]
Hence the correct answer is (A) i.e. Fructose given positive Fehling’s solution test is a true statement.
Additional information:
Fehling’s solution is prepared by mixing Fehling’s A and Fehling’s B. this solution acts as an oxidizing agent. Due to the presence of copper the solution gives blue color which on reaction with the aldehyde group turns the copper ions to copper oxide which appears as red precipitate.
The sugar having free aldehyde groups gets reduced but the one without the aldehyde group gives a negative test. The reaction involved is mentioned below:
$RCHO+2C{{u}^{2+}}+5O{{H}^{-}}\to RCO{{O}^{-}}+C{{u}_{2}}O+3{{H}_{2}}O$
Note:
The Fehling’s test is sensitive enough because 1 mg of glucose will be sufficient to produce the characteristic red color of the compound. This test is used to differentiate between the reducing sugars and non reducing sugars. And one more important point is that this test will turn out positive only when a free aldehyde group is present.
Recently Updated Pages
Identify the feminine gender noun from the given sentence class 10 english CBSE
Your club organized a blood donation camp in your city class 10 english CBSE
Choose the correct meaning of the idiomphrase from class 10 english CBSE
Identify the neuter gender noun from the given sentence class 10 english CBSE
Choose the word which best expresses the meaning of class 10 english CBSE
Choose the word which is closest to the opposite in class 10 english CBSE
Trending doubts
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Which are the Top 10 Largest Countries of the World?
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
How do you graph the function fx 4x class 9 maths CBSE
Discuss the main reasons for poverty in India
A Paragraph on Pollution in about 100-150 Words
Advantages and disadvantages of science
Why is monsoon considered a unifying bond class 10 social science CBSE
What makes elections in India democratic class 11 social science CBSE