Which among the following is expected to have the highest boiling point?

Options

A. 2-Methylpropane
B. n-Hexane
C. 2-Methylpentane
D. 2,2-Dimethylbutane

Answer

To determine which compound among the given options has the highest boiling point, we need to analyze the molecular structure and branching of each compound. The compounds provided are:

1. 2-methylpropane
2. n-hexane
3. 2-methylpentane
4. 2,2-dimethylbutane

### Step 1: Understand the Factors Affecting Boiling Point
The boiling point of alkanes is influenced by:
- Molecular mass: Higher molecular mass generally leads to a higher boiling point.
- Surface area: Increased surface area enhances van der Waals forces, leading to higher boiling points.
- Branching: More branching in the molecular structure decreases surface area and thus decreases boiling point.

### Step 2: Analyze Each Compound
1. **2-methylpropane (C5H12)**: This compound has a lower molecular mass and is branched, which typically results in a lower boiling point.
2. **n-hexane (C6H14)**: This is a straight-chain alkane with a higher molecular mass and no branching, which usually gives it a higher boiling point.
3. **2-methylpentane (C6H14)**: This compound has the same molecular mass as n-hexane but is branched. Therefore, it will have a lower boiling point than n-hexane.
4. **2,2-dimethylbutane (C6H14)**: This compound also has the same molecular mass as n-hexane and 2-methylpentane but is more branched than both, leading to an even lower boiling point.

### Step 3: Compare the Boiling Points
- **2-methylpropane**: Lowest boiling point due to lower molecular mass and high branching.
- **n-hexane**: Highest boiling point due to higher molecular mass and no branching.
- **2-methylpentane**: Intermediate boiling point due to moderate branching.
- **2,2-dimethylbutane**: Lower boiling point than n-hexane due to increased branching.

### Conclusion
Based on the analysis, **n-hexane** has the highest boiling point among the given compounds.

### Final Answer
The compound expected to have the highest boiling point is **n-hexane**.

---