The resistance of a conductivity cell containing 0.001M KCl solution at 298 K is 1500 Ω. What is the cell constant if conductivity of 0.001M KCl solution at 298 K is ⁻³ S cm⁻¹.
The cell constant is 0.219 cm⁻¹.
Explanation
This question tests the fundamental relationship between cell constant, resistance, and conductivity. The cell constant (G*) is defined as the ratio l/A and can be calculated using the formula G* = R × κ, where R is the measured resistance and κ is the known conductivity of the solution. The textbook explicitly states this relationship in equation 2.18 and demonstrates its application in Example 2.8 where a similar calculation is shown.
Solution Steps
Given: Resistance (R) = 1500 Ω, Conductivity (κ) = ⁻³ S cm⁻¹
Formula: Cell constant (G*) = R × κ
Calculation: G* = 1500 Ω × ⁻³ S cm⁻¹ = cm⁻¹ = 0.219 cm⁻¹
Answer: Cell constant = 0.219 cm⁻¹