**Question:** Lactose on hydrolysis yields -

**Core Concept:** Lactose is a disaccharide sugar found in milk, which is composed of glucose and galactose molecules. The process of hydrolysis involves breaking down complex molecules into simpler ones through the action of enzymes or acids.

**Why the Correct Answer is Right:** When lactose is hydrolyzed, it breaks down into two simpler molecules - glucose and galactose. This process is catalyzed by the enzyme lactase, which is produced by the small intestine lining. The correct answer is:

**Correct Answer: [Letter]. Hydrolysis of lactose yields glucose and galactose.**

**Why Each Wrong Option is Incorrect:**

A. **Lactulose:** Lactulose is a fructose-containing disaccharide sugar, not a result of lactose hydrolysis.
B. **Maltose:** Maltose is a disaccharide sugar formed from the hydrolysis of starch, not lactose.
C. **Ascorbic acid (Vitamin C):** Ascorbic acid is a vitamin, not a product of lactose hydrolysis.
D. **Lactic acid:** Lactic acid is produced during fermentation processes, not from lactose hydrolysis.

**Clinical Pearl / High-Yield Fact:** Hydrolysis of lactose is essential for individuals with lactose intolerance, as it helps break down lactose into glucose and galactose, which can be absorbed by the small intestine. Adequate lactase production prevents lactose from fermenting in the large intestine, causing symptoms associated with lactose intolerance.