Hydrolysis of lactose with dilute acid yields:

Options

A. Equimolar mixture of `D-`glucose and `D-`glucose.
B. Equimolar mixture of `D-`glucose and `D-`galactose..
C. Equimolar mixture of `D-`glucose and `D-`fructose.
D. Equimolar mixture of `D-`galactose and `D-`galactose.

Answer

To solve the question regarding the hydrolysis of lactose with dilute acid, we will follow these steps:

### Step 1: Understand the Structure of Lactose
Lactose is a disaccharide composed of two monosaccharides: β-D-galactose and α-D-glucose. These two sugars are linked by a glycosidic bond.

### Step 2: Write the Chemical Formula of Lactose
The chemical formula for lactose is C12H22O11. This formula indicates that lactose is made up of 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms.

### Step 3: Hydrolysis Reaction
Hydrolysis is a chemical reaction that involves the breaking of a bond in a molecule using water. In the case of lactose, hydrolysis can be catalyzed by dilute acids or enzymes.

The hydrolysis reaction can be represented as:
\[ \text{C}_{12}\text{H}_{22}\text{O}_{11} + \text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + \text{C}_6\text{H}_{12}\text{O}_6 \]

### Step 4: Products of Hydrolysis
Upon hydrolysis, lactose yields two molecules of monosaccharides:
- One molecule of D-glucose (C6H12O6)
- One molecule of D-galactose (C6H12O6)

### Step 5: Conclusion
Thus, the hydrolysis of lactose with dilute acid yields an equimolar mixture of D-galactose and D-glucose.

### Final Answer
The hydrolysis of lactose with dilute acid yields D-galactose and D-glucose in equimolar amounts.

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