Question

The conductivity of NaI solution is \( 6.0 \times 10^{-4} \, \Omega^{-1} \text{cm}^{-1} \) and molar conductivity is \( 120 \, \Omega^{-1} \text{cm}^2 \text{mol}^{-1} \). Calculate the concentration of NaI solution.

• A. 0.05 M
• B. \( 2 \times 10^{-2} \) M
• C. 0.005 M
• D. \( 7.2 \times 10^{-3} \) M

Hint:

To calculate the concentration from conductivity and molar conductivity, use the formula \( C = \frac{\kappa}{\Lambda_m} \).

Answer 1

The Correct Option is C

Step 1: Formula for molar conductivity.
The molar conductivity (\( \Lambda_m \)) is given by the formula: \[ \Lambda_m = \frac{\kappa}{C} \] Where: \(\kappa\) is the conductivity, \(C\) is the concentration. Step 2: Re-arranging the formula.
Re-arrange the formula to calculate the concentration: \[ C = \frac{\kappa}{\Lambda_m} \] Step 3: Substituting values.
Substitute the given values: \[ C = \frac{6.0 \times 10^{-4} \, \Omega^{-1} \text{cm}^{-1}}{120 \, \Omega^{-1} \text{cm}^2 \text{mol}^{-1}} = 0.005 \, \text{M} \] Step 4: Conclusion.
The concentration of NaI solution is 0.005 M, so the correct answer is (C).