carbohydrates-chemistry-jee-main-questions

Q 11 :

A D-aldotetrose on oxidation with concentrated ${HNO}_{3}$ resulted in optically inactive dicarboxylic acid. The structure of the D-aldotetrose is: [2026]

[IMAGE 283]
[IMAGE 284]
[IMAGE 285]
[IMAGE 286]

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(3)

[IMAGE 287]

Q 12 :

Identify the correct statements.

A. Glucose exists in two anomeric forms.

B. Anomers of glucose differ in configuration at C-1 in cyclic hemiacetal structure.

C. Melting point of $α$ -anomer of glucose is greater than $β$ -anomer.

D. Specific rotation of $α$ -anomer is $+ 19 °$ while for $β$ -anomer is $+ 112 °$ .

E. $α$ and $β$ -anomers of glucose are prepared by crystallisation of saturated glucose solution at 303 K and 371 K respectively.

Choose the correct answer from the options given below: [2026]

A and B only
B and C only
A, B and D only
A, B and E only

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(4)

[IMAGE 288]

Q 13 :

Given below are two statements:

Statement I: [IMAGE 289] are two anomers of D-(+)-glucose.

Statement II: The open chain forms of D-glucose and D-fructose contain three similar chiral carbons at $C_{3}$ , $C_{4}$ and $C_{5}$ .

In the light of the above statements choose the correct answer from the options given below: [2026]

Both Statement I and Statement II are true
Both Statement I and Statement II are false
Statement I is true but Statement II is false
Statement I is false but Statement II is true

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Statement I: The two cyclic hemiacetal forms of glucose differ only in the configuration of the hydroxyl group at C1, called anomeric carbon. Such isomers, i.e., $α$ -form and $β$ -form, are called anomers.

[IMAGE 290]

Statement II: D-glucose and D-fructose have three similar chiral carbons at C-3, C-4 and C-5.

[IMAGE 291]

Q 14 :

The incorrect statement from the following with respect to carbohydrates is: [2026]

All monosaccharides are reducing sugars.
The monosaccharides units obtained from hydrolysis of oligosaccharides are always the same.
Starch and cellulose are typical examples of polysaccharides, which are very high molecular weight compounds of more than ten monosaccharide units.
Open chain and cyclic structures co-exist at equilibrium that are responsible for certain properties as in the case of D-(+)-glucose.

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Monosaccharides obtained by hydrolysis of oligosaccharides may be same or different.

Topic Question Set

Q 11 :

A D-aldotetrose on oxidation with concentrated ${HNO}_{3}$ resulted in optically inactive dicarboxylic acid. The structure of the D-aldotetrose is: [2026]

Q 14 :

The incorrect statement from the following with respect to carbohydrates is: [2026]

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Topic Question Set

Q 11 : A D-aldotetrose on oxidation with concentrated HNO3 resulted in optically inactive dicarboxylic acid. The structure of the D-aldotetrose is: [2026]

Q 14 : The incorrect statement from the following with respect to carbohydrates is: [2026]

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Q 11 :

A D-aldotetrose on oxidation with concentrated ${HNO}_{3}$ resulted in optically inactive dicarboxylic acid. The structure of the D-aldotetrose is: [2026]

Q 14 :

The incorrect statement from the following with respect to carbohydrates is: [2026]