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प्रश्न
Give scientific reasons:
The disaccharide sucrose gives negative Tollens test while the disaccharide maltose gives a positive Tollens test.
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उत्तर
- The structure of sucrose contains glycosidic linkage between C-1 of α-glucose and C-2 of β-fructose.
- Since the potential aldehyde and ketone groups of both the monosaccharide units are involved in the formation of the glycosidic bond (i.e., α, β-1,2- glycosidic bond), sucrose is a non-reducing sugar and gives negative Tollen’s test.
- The glycosidic bond in maltose is in between C-1 of one glucose ring and C-4 of the other (i.e., α -1,4-glycosidic linkage).
- The hemiacetal group at C-1 of the second ring is not involved in the glycosidic linkage. Hence, maltose is a reducing sugar and gives positive Tollen’s test.
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संबंधित प्रश्न
Glucose on oxidation with dilute nitric acid gives _______________
Write the name of the unit to which glucose unit is linked to from sucrose.
Write chemical reaction for following conversions
glucose into gluconic acid
What is the action of the following reagents on glucose?
hydroxylamine
What is the action of the following reagents on glucose?
hydrogen iodide
Define carbohydrates.
Draw the Haworth projection structure of the following.
α-D-(–)-Fructofuranose
Write a commercial method for preparation of glucose.
Which of the following monosaccharides is a tetrose sugar?
Carbohydrates can contain which of the following chemical groups?
From the following identify the group that is exclusively consists of polysaccharides.
From the following which is a heteropolysaccharide?
Identify the WRONG statement.
Match the columns and select the correct option.
| Column I | Column II | ||
| i. | Starch | a. | Animal storage molecule |
| ii. | Cellulose | b. | Plant storage molecule |
| iii. | Glycogen | c. | Heparin |
| iv. | Heteropolysaccharide | d. | Plant cell wall component |
Which carbon atoms of α- D glucopyranose and β-D-fructofuranose respectively are linked together to form glycosidic linkage in sucrose?
Raffinose, sucrose and stachyose are respectively ____________.
All these carbohydrates contain \[\ce{1 -> 4β}\] glycosidic linkage, EXCEPT ____________.
4-O-(α-D-Glucopyranosyl)-D-glucopyranose is ____________.
Which one of the following is an oligosaccharide?
\[\ce{CH3 - CH2 - CH2 - Br ->[Na][dry ether] A ->[Cl2] B}\]
Identify the product B in the above reaction.
Which among the following statements is true for amylose?
What is the number of hydroxyl groups present in lactic acid?
When 2 moles of stachyose is hydrolyzed, the number of moles of galactose obtained is ____________.
On hydrolysis sucrose gives ____________.
What is the quantity of glucose obtained when 68.4 g of sucrose is hydrolyzed in laboratory under ideal condition?
(Molar mass of sucrose = 342 g mol−1)
Identify the number of oxygen atoms present in saccharic acid?
Which among the following reagents is used to obtain gluconic acid from glucose?
What is the product obtained when Br2 water reacts with glucose?
When one mole of lactose is hydrolysed, the hydrolysate contains ____________.
Complete hydrolysis of cellulose gives ____________.
Glucose is an aldose. Which one of the following reactions is not expected with glucose?
Classify the following into monosaccharides, oligosaccharides and polysaccharides.
Sucrose
Classify the following into monosaccharides, oligosaccharides and polysaccharides.
Lactose
The molecule of glucose is also called ______.
Lactose is made of ______.
A molecule of stachyose contains how many carbon atoms?
Which carbon atoms of fructose are bonded together through oxygen forming fructofuranose?
Match the Column I with Column II and choose the correct answer from options below:
| Column I | Column II |
| A. Purine | 1. Glycogen |
| B. Pyrimidine | 2. Cellulose |
| C. Structural polysaccharide | 3. Glucagon |
| D. Storage polysaccharide | 4. Adenine |
| 5. Cytosine |
Why carbohydrates are generally optically active.
Why carbohydrates are generally optically active?
Explain the hydrolysis of sucrose.
Why carbohydrates are generally optically active.
CH2 OH - CO - (CHOH)4 - CH2 OH is an example of ______.
Why are carbohydrates generally optically active?
Why carbohydrates are generally optically active.
\[\ce{CH2OH - CO - (CHOH)4 - CH2 OH}\] is an example of ______.
Two monosaccharides are held together by ______ bond.
Given below are two statements.
Statement I - Lactose on hydrolysis converts into glucose and galactose.
Statement II - Galactose also plays same role as glucose in respiration.
In light of the above statements, select the correct option given below.
What are the number of chiral carbon atoms and the number of formyl groups, respectively, present in ribose?
