Which of the following molecules has highest dipole moment?

Options

A. `CH_3Cl`
B. `CH_2Cl_2`
C. `CHCl_3`
D. `CCCl4`

Explanation

To determine which molecule has the highest dipole moment among the given options (CH3Cl, CH2Cl2, CHCl3, and CCl4), we can analyze the molecular structures and the contributions of individual bond dipoles to the overall dipole moment.

### Step-by-Step Solution:

1. **Identify the Molecular Structures**:
- **CH3Cl (Methyl Chloride)**: The structure consists of one carbon atom bonded to three hydrogen atoms and one chlorine atom.
- **CH2Cl2 (Dichloromethane)**: The structure consists of one carbon atom bonded to two hydrogen atoms and two chlorine atoms.
- **CHCl3 (Trichloromethane)**: The structure consists of one carbon atom bonded to one hydrogen atom and three chlorine atoms.
- **CCl4 (Carbon Tetrachloride)**: The structure consists of one carbon atom bonded to four chlorine atoms.

2. **Determine Electronegativity**:
- Chlorine (Cl) is more electronegative than carbon (C), and carbon is more electronegative than hydrogen (H). This means that the dipole moments will point towards chlorine in each case.

3. **Calculate the Dipole Moments**:
- **For CH3Cl**: The dipole moment from C to Cl is significant, while the dipole moments from C to H are smaller and point in the opposite direction. The net dipole moment is approximately 1.1 Debye.
- **For CH2Cl2**: The dipole moments from C to both Cl atoms add together, while the dipole moments from C to H atoms are smaller and point in the opposite direction. The net dipole moment is approximately 1.60 Debye.
- **For CHCl3**: The dipole moment from C to Cl atoms partially cancels with the dipole moment from C to H. The net dipole moment is reduced due to cancellation, approximately 0.9 Debye.
- **For CCl4**: The dipole moments from C to all four Cl atoms cancel each other out completely, resulting in a net dipole moment of 0 Debye.

4. **Compare the Dipole Moments**:
- From the calculated values, we see:
- CH3Cl: ~1.1 Debye
- CH2Cl2: ~1.60 Debye
- CHCl3: ~0.9 Debye
- CCl4: 0 Debye

5. **Conclusion**:
- The molecule with the highest dipole moment is **CH2Cl2 (Dichloromethane)**, with a dipole moment of approximately 1.60 Debye.

### Final Answer:
**CH2Cl2 (Dichloromethane) has the highest dipole moment.**