Which is the correct increasing order of boiling points of the following compounds ?
1-bromomethane, 1-bromobutane, 1-chlorobutane, 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

Explanation

To determine the correct increasing order of boiling points of the compounds 1-bromomethane, 1-bromobutane, 1-chlorobutane, and bromobenzene, we need to analyze the factors affecting boiling points, such as molecular weight, surface area, and intermolecular forces.

### Step-by-Step Solution:

1. **Identify the Compounds and Their Structures**:
- 1-bromomethane (CH3Br)
- 1-bromobutane (C4H9Br)
- 1-chlorobutane (C4H9Cl)
- Bromobenzene (C6H5Br)

2. **Consider the Molecular Weights**:
- 1-bromomethane: Molecular weight = 94.94 g/mol
- 1-bromobutane: Molecular weight = 137.99 g/mol
- 1-chlorobutane: Molecular weight = 92.93 g/mol
- Bromobenzene: Molecular weight = 157.01 g/mol

3. **Analyze the Intermolecular Forces**:
- **Van der Waals Forces**: These forces increase with molecular weight and surface area. Bromobenzene, being aromatic, has stronger π-π interactions.
- **Hydrogen Bonding**: Not applicable in these compounds, as they do not have -OH or -NH groups.

4. **Evaluate the Boiling Points Based on Molecular Weight and Structure**:
- 1-bromomethane has the lowest molecular weight and surface area, leading to the lowest boiling point.
- 1-chlorobutane, while having a similar molecular weight to 1-bromobutane, has a lower boiling point due to the weaker Van der Waals forces compared to the bromine atom.
- 1-bromobutane has a higher boiling point than both 1-bromomethane and 1-chlorobutane because of its larger molecular weight and surface area.
- Bromobenzene has the highest boiling point due to its high molecular weight and the presence of π-π interactions.

5. **Establish the Increasing Order of Boiling Points**:
- Based on the analysis, the order from lowest to highest boiling point is:
- 1-bromomethane < 1-chlorobutane < 1-bromobutane < bromobenzene

### Final Answer:
The correct increasing order of boiling points is:
**1-bromomethane < 1-chlorobutane < 1-bromobutane < bromobenzene**