n-Butyl bromide has higher boiling point than t-butyl bromide.

Answer

To understand why n-butyl bromide has a higher boiling point than t-butyl bromide, we can analyze the structures and intermolecular forces involved. Here’s a step-by-step solution:

### Step 1: Identify the Structures
- **n-Butyl bromide** (C4H9Br) has a straight-chain structure:
- Structure: CH3-CH2-CH2-CH2-Br
- **t-Butyl bromide** (C4H9Br) has a branched structure:
- Structure: (CH3)3C-Br

### Step 2: Analyze Surface Area
- n-Butyl bromide is a straight-chain alkyl halide, which means it has a larger surface area compared to t-butyl bromide, which is branched.
- A larger surface area allows for more contact between molecules.

### Step 3: Consider Intermolecular Forces
- The primary intermolecular forces in both compounds are Van der Waals forces (dispersion forces).
- Since n-butyl bromide has a larger surface area, it can exhibit stronger Van der Waals forces due to increased contact between molecules.

### Step 4: Relate Intermolecular Forces to Boiling Point
- The boiling point of a substance is influenced by the strength of its intermolecular forces.
- Stronger intermolecular forces require more energy to overcome, resulting in a higher boiling point.
- Therefore, the larger Van der Waals forces in n-butyl bromide lead to a higher boiling point compared to t-butyl bromide.

### Conclusion
- n-Butyl bromide has a higher boiling point than t-butyl bromide due to its larger surface area, which results in stronger Van der Waals forces.