Question

Which one of the following statements is not true regarding $(+)$ lactose?

• A. $(+)$ lactose is a $\beta$-glycoside formed by the union of a molecule of $D(+)$ glucose and a molecule of $D(+)$ galactose
• B. $(+)$ lactose is a reducing sugar and does not exhibit mutarotation
• C. $(+)$ lactose, $C_{12} H_{22}O_{11}$contains $8-OH$ groups
• D. On hydrolysis $(+)$ lactose gives equal amount of $D(+)$ glucose and $D(+)$ galactose

Answer 1

The Correct Option is B

 To determine the correct statement that is not true regarding \((+)\) lactose, let's evaluate each of the given options based on our understanding of the chemical properties of lactose:

1. \((+)\) lactose is a \(\beta\)-glycoside formed by the union of a molecule of \(D(+)\) glucose and a molecule of \(D(+)\) galactose.
2. \((+)\) lactose is a reducing sugar and does not exhibit mutarotation.
3. \((+)\) lactose, \(C_{12}H_{22}O_{11}\) contains \(8-OH\) groups.
4. On hydrolysis, \((+)\) lactose gives equal amounts of \(D(+)\) glucose and \(D(+)\) galactose.

Upon evaluation, the statement "\((+)\) lactose is a reducing sugar and does not exhibit mutarotation" is the incorrect one, as lactose does exhibit mutarotation.