Which one of the following is liquid at room temperature?

Options

A. `CH_3Cl`
B. `C_2H_5Cl`
C. `CH_3Br`
D. `C_2H_5Br`

Answer

To determine which of the following compounds is a liquid at room temperature, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Compounds**: The options given are methyl chloride, ethyl chloride, methyl bromide, and ethyl bromide.

2. **Check the State of Each Compound at Room Temperature**:
- **Methyl Chloride (CH₃Cl)**: This compound is known to be a gas at room temperature.
- **Ethyl Chloride (C₂H₅Cl)**: This compound is also a gas at room temperature.
- **Methyl Bromide (CH₃Br)**: This compound is similarly a gas at room temperature.
- **Ethyl Bromide (C₂H₅Br)**: This compound is known to exist as a liquid at room temperature.

3. **Conclusion**: Based on the analysis, ethyl bromide (C₂H₅Br) is the only compound that is a liquid at room temperature.

### Final Answer:
The compound that is liquid at room temperature is **Ethyl Bromide (C₂H₅Br)**.

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