Question

Given below are two statements:
Statement I: Fructose does not contain an aldehydic group but still reduces Tollen’s reagent.
Statement II: In the presence of base, fructose undergoes rearrangement to give glucose.
In the light of the above statements, choose the correct answer from the options given below.

• A. Statement I is false but Statement II is true
• B. Both Statement I and Statement II are true
• C. Both Statement I and Statement II are false
• D. Statement I is true but Statement II is false

Hint:

Fructose is a ketose, but it has the ability to reduce Tollen's reagent due to the equilibrium with its aldose form. Always remember that sugar rearrangements can convert between different types of sugars, like ketoses to aldoses.

Answer 1

The Correct Option is B

Statement I is correct because fructose, while not having an aldehyde group in its structure, can still reduce Tollen's reagent. This is because fructose exists as an equilibrium mixture of two anomers, one of which contains a free aldehyde group. This allows it to reduce Tollen's reagent. Statement II is also correct because, in the presence of a base, fructose undergoes a rearrangement to form glucose through an enediol intermediate. This reaction is known as the Lobry de Bruyn–Alberda van Ekenstein transformation.