The compound with the highest boiling point is:

Options

A. (a) n-Pentane
B. (b) n-Hexane
C. (c) 2-Methyl butane
D. (d) 2,2-Dimethyl propane

Explanation

To determine which compound has the highest boiling point among the given options, we can follow these steps:

### Step 1: Identify the Compounds
We have four compounds to analyze:
1. n-Pentane (C5H12)
2. Hexane (C6H14)
3. 2-Methylbutane (C5H12)
4. 2,2-Dimethylbutane (C5H12)

### Step 2: Understand the Factors Affecting Boiling Point
The boiling point of alkanes is influenced by:
- The number of carbon atoms: More carbon atoms generally lead to higher boiling points due to increased van der Waals forces.
- The degree of branching: More branching typically leads to lower boiling points because branched molecules are more compact and have less surface area for intermolecular interactions.

### Step 3: Count Carbon Atoms and Analyze Branching
- **n-Pentane**: 5 carbon atoms, straight-chain (no branching).
- **Hexane**: 6 carbon atoms, straight-chain (no branching).
- **2-Methylbutane**: 5 carbon atoms, branched.
- **2,2-Dimethylbutane**: 5 carbon atoms, more branched than 2-methylbutane.

### Step 4: Compare the Boiling Points
1. **n-Pentane**: 5 carbons, straight-chain → Higher boiling point than branched isomers.
2. **Hexane**: 6 carbons, straight-chain → Expected to have the highest boiling point due to the highest number of carbon atoms.
3. **2-Methylbutane**: 5 carbons, branched → Lower boiling point than n-pentane.
4. **2,2-Dimethylbutane**: 5 carbons, more branched → Lowest boiling point among the four.

### Conclusion
Based on the analysis, **Hexane** (C6H14) has the highest boiling point because it has the most carbon atoms and is unbranched.

### Final Answer
The compound with the highest boiling point is **Hexane**.

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