Lactose on hydrolysis with dil.HCl gives

Options

A. Glucose and fructose
B. Glucose and mannose
C. Fructose and mannose
D. Glucose and galactose

Answer

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

### Step-by-Step Solution:

1. **Identify the Structure of Lactose**:
Lactose is a disaccharide composed of two monosaccharides: glucose and galactose. It has a β(1→4) glycosidic bond linking these two sugars.

2. **Chemical Formula of Lactose**:
The molecular formula of lactose is C12H22O11.

3. **Understand Hydrolysis**:
Hydrolysis is a chemical reaction that involves the breaking of a bond in a molecule using water. In this case, the glycosidic bond in lactose will be broken in the presence of dilute HCl (which acts as a catalyst).

4. **Products of Hydrolysis**:
When lactose undergoes hydrolysis, it will yield two monosaccharides:
- D-glucose
- D-galactose

5. **Write the Reaction**:
The reaction can be represented as follows:
\[ \text{C}_{12}\text{H}_{22}\text{O}_{11} + \text{H}_2\text{O} \xrightarrow{\text{dil. HCl} } \text{C}_6\text{H}_{12}\text{O}_6 (\text{glucose}) + \text{C}_6\text{H}_{12}\text{O}_6 (\text{galactose}) \]

6. **Conclusion**:
Therefore, the hydrolysis of lactose with dilute HCl gives an equimolar mixture of glucose and galactose.

### Final Answer:
Lactose on hydrolysis with dilute HCl gives glucose and galactose.

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