The dipole moments of `CCl _ 4, CHCl _ 3 and CH _ 4 ` are in the order :

Options

A. `CH_4lt"CC"l_4ltCHCl_3`
B. `CHCl_3ltCH_4="CCl"_4`
C. `CH_4="CCl"_4gtCHCl_3`
D. `"CCl"_4ltCH_4ltCHCl_3`

Answer

To determine the order of dipole moments for the compounds CCl₄, CHCl₃, and CH₄, we can analyze the molecular geometry and electronegativity of the atoms involved.

### Step-by-Step Solution:

1. **Identify the Molecular Structures:**
- **CH₄ (Methane):** The molecule has a tetrahedral structure with four hydrogen atoms bonded to a central carbon atom.
- **CCl₄ (Carbon Tetrachloride):** This molecule also has a tetrahedral structure, but with four chlorine atoms bonded to the central carbon atom.
- **CHCl₃ (Chloroform):** Chloroform has a tetrahedral structure as well, with three chlorine atoms and one hydrogen atom bonded to the central carbon atom.

2. **Determine Electronegativity:**
- The electronegativity values are important in determining the dipole moment. In this case:
- Carbon (C) has an electronegativity of about 2.5.
- Hydrogen (H) has an electronegativity of about 2.1.
- Chlorine (Cl) has a higher electronegativity of about 3.0.

3. **Analyze Dipole Moments:**
- **CH₄:** Since all four bonds (C-H) are identical and symmetrical, the dipole moments cancel each other out. Thus, the dipole moment (µ) is 0.
- **CCl₄:** Similarly, in CCl₄, the four C-Cl bonds are also symmetrical, and the dipole moments cancel out, resulting in a dipole moment (µ) of 0.
- **CHCl₃:** In CHCl₃, the presence of one hydrogen atom creates an asymmetry. The three C-Cl bonds will pull electron density towards chlorine, while the C-H bond will pull some electron density towards carbon. This results in a net dipole moment greater than 0.

4. **Order of Dipole Moments:**
- Since both CH₄ and CCl₄ have a dipole moment of 0, and CHCl₃ has a dipole moment greater than 0, we can conclude that:
- µ(CH₄) = 0
- µ(CCl₄) = 0
- µ(CHCl₃) > 0
- Therefore, the order of dipole moments is:
- CH₄ = CCl₄ < CHCl₃

5. **Final Answer:**
- The correct order of dipole moments is: **CH₄ = CCl₄ < CHCl₃**.