Assertion: The boiling point of the compounds increases in the order:
Isopropylchloridelt1-Chloropropane,1-Chlorobutane. ltbr. Reason: Boiling point depends upon the molecular mass and surface area.

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 assetion is true but reason is false.
D. If both assertion and reason are false.

Answer

To solve the question, we need to analyze the assertion and reason provided regarding the boiling points of isopropyl chloride, 1-chloropropane, and 1-chlorobutane.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
The assertion states that the boiling point of the compounds increases in the order: isopropyl chloride < 1-chloropropane < 1-chlorobutane.

2. **Analyzing the Compounds**:
- **Isopropyl Chloride**: This compound has a branched structure, which generally leads to lower boiling points due to decreased surface area and weaker van der Waals forces.
- **1-Chloropropane**: This compound has a straight-chain structure, which allows for more surface area contact between molecules, leading to higher boiling points compared to branched compounds.
- **1-Chlorobutane**: This compound has a longer carbon chain than 1-chloropropane, resulting in even higher molecular mass and surface area, thus a higher boiling point.

3. **Comparing Boiling Points**:
- Isopropyl chloride has the lowest boiling point due to its branched structure.
- 1-chloropropane has a higher boiling point than isopropyl chloride due to its straight-chain structure.
- 1-chlorobutane has the highest boiling point because it has the longest carbon chain and the highest molecular mass.

4. **Conclusion on the Assertion**:
The assertion is correct as it accurately reflects the order of boiling points:
**Isopropyl chloride < 1-chloropropane < 1-chlorobutane**.

5. **Understanding the Reason**:
The reason states that boiling point depends upon molecular mass and surface area. This statement is also true. Boiling points are influenced by molecular mass (higher mass typically leads to higher boiling points) and surface area (more surface area allows for stronger intermolecular forces).

6. **Conclusion on the Reason**:
The reason is correct and provides a valid explanation for the assertion.

7. **Final Answer**:
Since both the assertion and reason are true, and the reason correctly explains the assertion, the answer is:
**A: Both assertion and reason are true, and reason is the correct explanation of assertion.**