Which one of the following does not exhibit the phenomenon of mutarotation ?

Options

A. (+)sucrose
B. (+) lactose
C. (+) Maltose
D. (-) Fructose

Answer

A

Explanation

Key idea reducing sugars that exist in hemiacetal and hemiketal forms, exhibit the phenomenon of mutarotation in aqueous solution. During mutarotaiton, the ring open upto give the open chain form which the reclose eithe rin the inverted position of in the original position giving an equilibrium mixture of two anomers with a small amount of open chain form. thus, all reducingmonosaccharides 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.