Assertion: Hydrolysis of sucrose brings about a change in sign of rotation from dextro to laevo.
Reason: Hydrolysis always changes the optical rotation of a compound.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To analyze the assertion and reason provided in the question, we will break down the concepts involved step by step.

### Step-by-Step Solution:

1. **Understanding Sucrose**:
- Sucrose is a disaccharide composed of glucose and fructose. It is known to be dextro-rotatory, meaning it rotates plane-polarized light to the right (clockwise). The specific rotation of sucrose is +66.5°.

**Hint**: Recall that "dextro" refers to rightward rotation and is denoted by a positive angle.

2. **Hydrolysis of Sucrose**:
- When sucrose undergoes hydrolysis, it breaks down into its constituent monosaccharides: glucose and fructose. This reaction can be catalyzed by acids or enzymes.

**Hint**: Hydrolysis involves the addition of water to break chemical bonds.

3. **Optical Activity of Glucose and Fructose**:
- Glucose is also dextro-rotatory with a specific rotation of +52.7°, while fructose is levo-rotatory with a specific rotation of -92.4°.

**Hint**: Remember that "levo" refers to leftward rotation and is denoted by a negative angle.

4. **Resulting Optical Rotation**:
- When sucrose is hydrolyzed, the resulting mixture contains both glucose and fructose. The presence of fructose, which has a significant negative rotation, causes the overall rotation of the mixture to become negative.

**Hint**: The net optical rotation of a mixture depends on the specific rotations and concentrations of the components.

5. **Change in Sign of Rotation**:
- The hydrolysis of sucrose results in a change in the sign of optical rotation from positive (dextro) to negative (levo) due to the predominance of levorotatory fructose in the mixture.

**Hint**: A mixture can exhibit different optical activity than its individual components.

6. **Assertion and Reason Evaluation**:
- The assertion states that hydrolysis of sucrose changes the sign of rotation from dextro to levo, which is true.
- The reason states that hydrolysis always changes the optical rotation of a compound, which is not universally true for all compounds (some may not exhibit optical activity).

**Hint**: Distinguish between specific cases and general statements when evaluating assertions and reasons.

### Conclusion:
- The assertion is true: Hydrolysis of sucrose does change the sign of rotation from dextro to levo.
- The reason is false: Hydrolysis does not always change the optical rotation of every compound.

### Final Answer:
- Assertion: True
- Reason: False