Which of the following has highest dipole moment in the following ?

Options

A. `CH_(3)F`
B. `CH_(3)Cl`
C. `C Cl_(4)`
D. `CH_(3)I`

Answer

To determine which of the given compounds has the highest dipole moment, we will analyze the dipole moments of CH3F, CH3Cl, CH3I, and CCl4 step by step.

### Step 1: Understand the Concept of Dipole Moment
Dipole moment (\( \mu \)) is a measure of the separation of positive and negative charges in a molecule. It depends on two factors:
1. The magnitude of the charge (which is influenced by the electronegativity of the atoms).
2. The distance between the charges (bond length).

### Step 2: Compare Electronegativity
- **Fluorine (F)** is more electronegative than **Chlorine (Cl)**, and **Chlorine (Cl)** is more electronegative than **Iodine (I)**. Therefore, the order of electronegativity is:
\[ F > Cl > I \]
- This means that in CH3F, CH3Cl, and CH3I, the dipole moments will be influenced by the electronegativity differences between carbon and the halogens.

### Step 3: Analyze Each Compound
1. **CH3F (Methyl Fluoride)**:
- The bond dipole moment is significant due to the high electronegativity of fluorine.
- However, the bond length (C-F) is relatively short.

2. **CH3Cl (Methyl Chloride)**:
- Chlorine is less electronegative than fluorine, but the bond length (C-Cl) is longer than C-F.
- The dipole moment is influenced by both the charge and the distance. The larger bond length compensates for the lower electronegativity compared to fluorine.

3. **CH3I (Methyl Iodide)**:
- Iodine has a lower electronegativity than chlorine, and the bond length (C-I) is even larger than C-Cl.
- The charge difference is less significant due to the similar electronegativities of carbon and iodine.

4. **CCl4 (Carbon Tetrachloride)**:
- CCl4 is a symmetrical molecule. Although each C-Cl bond has a dipole moment, they cancel each other out due to symmetry, resulting in a net dipole moment of zero.

### Step 4: Compare Dipole Moments
- **CH3F** has a significant dipole moment due to the high electronegativity of fluorine, but the short bond length reduces its overall dipole moment.
- **CH3Cl** has a balance of charge and bond length, leading to a higher dipole moment than CH3F.
- **CH3I** has a lower dipole moment than CH3Cl due to the reduced charge difference.
- **CCl4** has a dipole moment of zero.

### Conclusion
After analyzing all the compounds, we find that **CH3Cl (Methyl Chloride)** has the highest dipole moment among the given options.

### Final Answer
The compound with the highest dipole moment is **CH3Cl**.