Which is the correct increasing order of boiling points of the following compounds ?
1-Bromoethane, 1-Bromopropane, 1-Bromobutane, Bromobenzene

Options

A. `"Bromobenzene" lt "1-Bromobutane" lt "1-Bromopropane" lt "1-Bromoethane"`
B. `"Bromobenzene" lt "1-Bromoethane" lt "1-Bromopropane" lt "1-Bromobutane"`
C. `"1-Bromopropane" lt "1-Bromobutane" lt "1-Bromoethane" lt "Bromobenzene"`
D. `"1-Bromoethane" lt "1-Bromopropane" lt "1-Bromobutane" lt "Bromobenzene"`

Answer

To determine the correct increasing order of boiling points for the compounds 1-Bromoethane, 1-Bromopropane, 1-Bromobutane, and Bromobenzene, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Compounds**:
- 1-Bromoethane (C2H5Br)
- 1-Bromopropane (C3H7Br)
- 1-Bromobutane (C4H9Br)
- Bromobenzene (C6H5Br)

2. **Understand the Factors Affecting Boiling Points**:
- The boiling point of haloalkanes generally increases with an increase in the number of carbon atoms in the alkyl chain due to increased van der Waals forces.
- The presence of branching in the alkyl chain decreases the boiling point.
- Aromatic compounds like Bromobenzene have different properties due to their ring structure and resonance, which can also affect boiling points.

3. **Analyze Each Compound**:
- **1-Bromoethane**: Has the shortest carbon chain (2 carbons), leading to the lowest boiling point.
- **1-Bromopropane**: Has a longer carbon chain (3 carbons) than 1-Bromoethane, thus a higher boiling point.
- **1-Bromobutane**: Contains 4 carbons, which gives it a higher boiling point than both 1-Bromoethane and 1-Bromopropane.
- **Bromobenzene**: Although it has a ring structure, it has a significant number of carbon atoms (6). The presence of the aromatic ring contributes to a higher boiling point due to stronger intermolecular forces compared to the straight-chain haloalkanes.

4. **Determine the Increasing Order**:
- Based on the analysis, the order from lowest to highest boiling point is:
- 1-Bromoethane < 1-Bromopropane < 1-Bromobutane < Bromobenzene

### Final Answer:
The correct increasing order of boiling points is:
**1-Bromoethane < 1-Bromopropane < 1-Bromobutane < Bromobenzene**