The electrical resistance of a aqueous solution of an unknown strong electrolyte is measured to be a — Electrochemistry Chemistry Question
Question
The electrical resistance of a $0.01\text{ M}$ aqueous solution of an unknown strong electrolyte is measured to be $210\,\Omega$ at $298\text{ K}$ inside a specialized cell characterized by a geometric cell constant of exactly $0.84\text{ cm}^{-1}$. Calculate the precise molar conductivity ($\Lambda_m$) of this specific solution in $\text{S cm}^2\text{ mol}^{-1}$.
💡 Solution & Explanation
First, calculate the specific conductance (conductivity, $\kappa$) using $\kappa = \frac{1}{R} \times (\text{cell constant})$. $\kappa = \frac{1}{210} \times 0.84 = \frac{0.84}{210} = 0.004\text{ S cm}^{-1}$. Then, utilize the standard formula for molar conductivity: $\Lambda_m = \frac{\kappa \times 1000}{M}$. Substituting the knowns: $\Lambda_m = \frac{0.004 \times 1000}{0.01} = \frac{4}{0.01} = 400\text{ S cm}^2\text{ mol}^{-1}$.