Question

What will happen when $$D - \left( + \right) - $$  glucose is treated with methanolic $$-HCl$$   followed by Tollens’ reagent ?

A. A black $$ppt.$$  will be formed
B. A red $$ppt.$$  will be formed
C. A green colour will appear
D. No characteristic colour or $$ppt.$$  will be formed.  
Answer :   No characteristic colour or $$ppt.$$  will be formed.
Solution :
Reaction of $$D - \left( + \right) - $$  glucose with methanolic $$-HCl$$   leads to formation of methyl glucoside ( $${C_1} - OH$$   group is methylated ) which, being acetal, is not hydrolysable by base, so it will not respond Tollen’s reagent.

Releted MCQ Question on
Organic Chemistry >> Biomolecules

Releted Question 1

The pair of compounds in which both the compounds give positive test with Tollen’s reagent is

A. Glucose and Sucrose
B. Fructose and Sucrose
C. Acetophenone and Hexanal
D. Glucose and Fructose
Releted Question 2

The two forms of $$D - $$ glucopyranose obtained from the solution of $$D - $$ glucose are called

A. Isomers
B. Anomers
C. Epimers
D. Enantiomers
Releted Question 3

Cellulose upon acetylation with excess acetic anhydride/ $${H_2}S{O_4}$$  (catalytic) gives cellulose triacetate whose structure is

A. Biomolecules mcq option image
B. Biomolecules mcq option image
C. Biomolecules mcq option image
D. Biomolecules mcq option image
Releted Question 4

The following carbohydrate is
Biomolecules mcq question image

A. a ketohexose
B. an aldohexose
C. an $$\alpha $$ - furanose
D. an $$\alpha $$ - pyranose

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Biomolecules


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