The molecule which has the largest dipole moment amongst the following is

Options

A. `CH_(4)`
B. `CHCl_(3)`
C. `C Cl_(4)`
D. `CHl_(3)`

Answer

To determine which molecule has the largest dipole moment among the given options (CH4, CHCl3, CCl4, and CHI3), we will analyze the molecular structures and the electronegativities of the atoms involved.

### Step-by-Step Solution:

1. **Analyze CH4 (Methane)**:
- Structure: The molecule consists of one carbon atom bonded to four hydrogen atoms (C-H bonds).
- Electronegativity: Carbon (C) has an electronegativity of about 2.5, while hydrogen (H) has an electronegativity of about 2.1.
- Dipole Moment: The C-H bonds have a small dipole moment, but due to the symmetrical tetrahedral shape, all dipole moments cancel each other out.
- **Net Dipole Moment**: Zero.

2. **Analyze CHCl3 (Chloroform)**:
- Structure: The molecule consists of one carbon atom bonded to one hydrogen atom and three chlorine atoms (C-H and C-Cl bonds).
- Electronegativity: Chlorine (Cl) has an electronegativity of about 3.0, which is greater than that of carbon.
- Dipole Moment: The C-Cl bonds will have a significant dipole moment directed towards chlorine, while the C-H bond has a smaller dipole moment directed towards hydrogen.
- **Net Dipole Moment**: Not zero, and it has a significant value due to the three C-Cl bonds.

3. **Analyze CCl4 (Carbon Tetrachloride)**:
- Structure: The molecule consists of one carbon atom bonded to four chlorine atoms (C-Cl bonds).
- Electronegativity: Similar to CHCl3, chlorine is more electronegative than carbon.
- Dipole Moment: Although each C-Cl bond has a dipole moment, the molecule is symmetrical (tetrahedral), which means the dipole moments cancel each other out.
- **Net Dipole Moment**: Zero.

4. **Analyze CHI3 (Iodoform)**:
- Structure: The molecule consists of one carbon atom bonded to one hydrogen atom and three iodine atoms (C-H and C-I bonds).
- Electronegativity: Iodine (I) has an electronegativity of about 2.7, which is less than chlorine but more than hydrogen.
- Dipole Moment: The C-I bonds have a dipole moment directed towards iodine, and the C-H bond has a smaller dipole moment directed towards hydrogen.
- **Net Dipole Moment**: Not zero, but less than that of CHCl3 because iodine is less electronegative than chlorine.

5. **Comparison of Dipole Moments**:
- CH4: Net dipole moment = 0
- CHCl3: Significant net dipole moment due to three C-Cl bonds.
- CCl4: Net dipole moment = 0
- CHI3: Net dipole moment is present but less than CHCl3.

### Conclusion:
The molecule with the largest dipole moment among the given options is **CHCl3 (Chloroform)**.