Question

The molar conductivity of $0.02 \text{ moldm}^{-3}$ solution of sodium hydroxide is $230.5 \, \Omega^{-1} \text{ cm}^2 \text{ mol}^{-1}$. What is it's conductivity?

• A. $0.01155 \, \Omega^{-1} \text{ cm}^{-1}$
• B. $0.02308 \, \Omega^{-1} \text{ cm}^{-1}$
• C. $0.00461 \, \Omega^{-1} \text{ cm}^{-1}$
• D. $0.05613 \, \Omega^{-1} \text{ cm}^{-1}$

Hint:

Formula: $\kappa = \frac{\Lambda_m \times C}{1000}$

Answer 1

The Correct Option is C

Concept: Relation between molar conductivity ($\Lambda_m$) and conductivity ($\kappa$): \[ \Lambda_m = \frac{\kappa \times 1000}{C} \Rightarrow \kappa = \frac{\Lambda_m \times C}{1000} \]

Step 1: Substitute values. \[ \kappa = \frac{230.5 \times 0.02}{1000} \]

Step 2: Calculate. \[ \kappa = \frac{4.61}{1000} = 0.00461 \, \Omega^{-1} \text{ cm}^{-1} \]

Step 3: Conclusion.
Thus, conductivity = $0.00461 \, \Omega^{-1} \text{ cm}^{-1}$. Final Answer: Option (C)