Which of the following has highest boilling point ?

Options

A. 1-chloropentane
B. 2-chloropentane
C. 3-chloropentane
D. All have equal boilling point

Answer

To determine which of the following compounds has the highest boiling point among 1-chloropentane, 2-chloropentane, and 3-chloropentane, we will analyze their structures and molecular interactions step by step.

### Step 1: Write the Structures of Each Compound
1. **1-Chloropentane**: This compound has a chlorine atom attached to the first carbon of a five-carbon straight chain (pentane).
- Structure: CH3-CH2-CH2-CH2-CH2Cl

2. **2-Chloropentane**: Here, the chlorine atom is attached to the second carbon of the pentane chain.
- Structure: CH3-CHCl-CH2-CH2-CH3

3. **3-Chloropentane**: In this case, the chlorine atom is attached to the third carbon of the pentane chain.
- Structure: CH3-CH2-CHCl-CH2-CH3

### Step 2: Analyze the Molecular Mass and Surface Area
- **Molecular Mass**: All three compounds have the same molecular formula (C5H11Cl), but the arrangement of atoms affects their boiling points.
- **Surface Area**: 1-chloropentane is a straight-chain molecule, while 2-chloropentane and 3-chloropentane are branched. Generally, straight-chain alkanes have higher boiling points than their branched counterparts due to greater surface area, which enhances Van der Waals forces.

### Step 3: Compare the Boiling Points
- **1-Chloropentane**: Being a straight-chain molecule, it has a larger surface area, leading to stronger intermolecular forces (Van der Waals forces).
- **2-Chloropentane and 3-Chloropentane**: These are branched, which reduces their surface area and consequently their ability to interact through Van der Waals forces.

### Conclusion
Based on the analysis, 1-chloropentane has the highest boiling point among the three compounds due to its straight-chain structure, which allows for stronger intermolecular interactions.

**Final Answer**: 1-Chloropentane has the highest boiling point.

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