Question

Which of the following does not exihibit the phenomena of mutarotation?

• A. (+) Sucrose
• B. (+) Lactose
• C. (+) Maltose
• D. (-) Fructose

Answer 1

Answer: (A)

(+) Sucrose

Answer 2

The correct answer is A:(+)Sucrose
Reducing sugars that exist in hemiacetal and hemiketal forms, mutarotation in aqueous solution. During mutarotation, the ring open upto give the open chain form which then reclose either in the inverted position or in the original position giving an equilibrium mixture of two anomers with a small amount of open chain form. Thus, all reducing mono saccharides and disaccharides undergo mutarotation in aqueous solution.
Among the given carbohydrates, only sucrose is a non-reducing sugar as in it the hemiacetal and hemiketal groups of glucose and fructose are linked together through O-atom and thus, not free. Due to the absence of free hemiacetal or hemiketal group, sucrose does not exhibit
mutarotation.