Question

What will be the concentration of NaCl solution, if the molar conductivity and conductivity of NaCl solution are 124.3 \(\Omega^{-1}\)cm\(^2\)mol\(^{-1}\) and 1.243 × 10\(^-4\) \(\Omega^{-1}\)cm\(^1\) respectively?

• A. 0.001 mol L\(^{-1}\)
• B. 0.01 mol L\(^{-1}\)
• C. 0.02 mol L\(^{-1}\)
• D. 0.1 mol L\(^{-1}\)

Hint:

Molar conductivity (\(\lambda_m\)) can be used to calculate concentration using the formula \(\lambda_m = \frac{\kappa}{C}\).

Answer 1

The Correct Option is A

Step 1: Formula for molar conductivity.
Molar conductivity \(\lambda_m\) is related to conductivity \(\kappa\) and concentration \(C\) by the equation: \[ \lambda_m = \frac{\kappa}{C} \]
Step 2: Calculation.
Substitute the given values: \[ 124.3 = \frac{1.243 \times 10^{-4}}{C} \] Solving for \(C\): \[ C = \frac{1.243 \times 10^{-4}}{124.3} = 0.001 \, \text{mol L}^{-1} \]
Step 3: Conclusion.
The concentration of NaCl solution is 0.001 mol L\(^{-1}\).