Q. Which one of the following statements is not true regarding (+) Lactose?
A) (+) Lactose, C₁₂H₂₂O₁₁ contains 8 –OH groups
B) On hydrolysis (+) Lactose gives equal amount of D(+) glucose and D(+) galactose
C) (+) Lactose is a β-glycoside formed by the union of a molecule of D(+) glucose and a molecule of D(+) galactose
D) (+) Lactose is a reducing sugar and does not exhibit mutarotation
Explanation
[Solution from source] Lactose has a free hemiacetal group on its glucose unit, so it is a reducing sugar and does show mutarotation; the statement that it does not mutarotate is false. It has 8 –OH groups, is a β-glycoside of D-galactose and D-glucose, and hydrolyses to equal amounts of the two. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.