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प्रश्न
Write the reactions of D-glucose which can’t be explained by its open-chain structure. How can cyclic structure of glucose explain these reactions?
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उत्तर
Following reactions and facts could not be explained by open-chain structures of glucose.
• Despite having the aldehyde group, glucose does not give 2, 4 − DNP test, Schiff's test and it does not form the hydrogen sulphide addition product with \[\ce{NaHSO3}\].
• The pentaacetate of glucose does not react with hydroxylamine indicating the absence of a free −CHO group.
It was proposed that one of the −OH groups may add to the −CHO group and form a cyclic hemiacetal structure. It was found that glucose forms a six-membered ring in which −OH at C − 5 is involved in a ring formation.
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संबंधित प्रश्न
Enumerate the reactions of D-glucose which cannot be explained by its open chain structure.
Glucose on reaction with HI gives n-hexane. What does it suggest about the structure of glucose?
Answer the following question.
What is the basic structural difference between glucose and fructose?
What is the most abundant organic compound on earth?
Oxime is formed by treating glucose with ____________.
Which of the following statements is incorrect regarding glucose?
Which one of the following compounds is different from the rest?
Glucose reacts with acetic anhydride to form ______.
A solution of D-glucose in water rotates the plane polarised light ____________.
The two forms of D-glucopyranose obtained from the solution of D-glucose are called ____________.
Which one is correct?
Which of the following pairs represents anomers?
What happens when D-glucose is treated with the following reagent?
HI
Account for the following:
What happens when D – glucose is treated with the following reagents
Bromine water
Glucose with excess of phenyl hydrazine forms ______.
Match List - I with List - II.
| List I | List II | ||
| (A) | Glucose + HI | (I) | Gluconic acid |
| (B) | Glucose + Br2 water | (II) | Glucose pentacetate |
| (C) | Glucose + acetic anhydride | (III) | Saccharic acid |
| (D) | Glucose + HNO3 | (IV) | Hexane |
Choose the correct answer from the options given below:
Give a reason for the following observations:
Penta-acetate of glucose does not react with hydroxylamine.
The reagents with which glucose does not react to give the corresponding tests/products are:
- Tollen’s reagent
- Schiff’s reagent
- HCN
- NH2OH
- NaHSO3
Choose the correct options from the given below:
