The value of molar conductivity of HCl is greater than that of NaCl at a particular temperature because :

Options

A. Molecular mass of HCl is less than that of NaCl
B. Velocity of `H^(+)` ions is more than that of `Na^(+)` ions
C. HCl is strongly acidic
D. Ionization of HCl is greater than that of NaCl

Answer

To determine why the molar conductivity of HCl is greater than that of NaCl at a particular temperature, we can analyze the properties of the ions produced by these electrolytes and their effects on conductivity.

### Step-by-Step Solution:

1. **Understanding Molar Conductivity**:
- Molar conductivity (\( \Lambda_m \)) is defined as the conductivity of an electrolyte solution divided by its molar concentration. It indicates how well an electrolyte conducts electricity when dissolved in water.

2. **Dissociation of Electrolytes**:
- HCl dissociates in water to form H⁺ ions and Cl⁻ ions:
\[ \text{HCl} \rightarrow \text{H}^+ + \text{Cl}^- \]
- NaCl dissociates in water to form Na⁺ ions and Cl⁻ ions:
\[ \text{NaCl} \rightarrow \text{Na}^+ + \text{Cl}^- \]

3. **Comparing the Ions**:
- Both HCl and NaCl produce Cl⁻ ions, which are the same in both cases. Therefore, the difference in molar conductivity will depend on the cations: H⁺ and Na⁺.

4. **Size and Velocity of Ions**:
- The mobility (velocity) of an ion in solution is influenced by its size. Smaller ions generally move faster than larger ions.
- H⁺ (hydrogen ion) is smaller than Na⁺ (sodium ion). This smaller size allows H⁺ to move more quickly through the solution.

5. **Conductivity and Ion Mobility**:
- Conductivity is directly proportional to the mobility of the ions in solution. Since H⁺ has a greater mobility than Na⁺, it contributes more significantly to the overall conductivity of the solution.

6. **Conclusion**:
- Therefore, the molar conductivity of HCl is greater than that of NaCl primarily because the H⁺ ion has a higher velocity than the Na⁺ ion due to its smaller size.

### Final Answer:
The molar conductivity of HCl is greater than that of NaCl at a particular temperature because the velocity of H⁺ ions is more than that of Na⁺ ions.