Resistance of a conductivity cell filled with 0.1 M is 100 ohm. If the resistance of the same cell when filled with 0.02 M KCl solution is 520 ohms, calculate the conductivity and molar conductivity of the 0.02 M KCl solution. Conductivity of 0.1 M KCl solution is 1.29*10-2 S cm-1.
Cell constant can be calculated using 0.1 M KCl
= κ × R
= 0.0129 * 100
= 1.29 cm-1
Calculating conductivity of 0.02 M KCl solution
κ = Cell constant / Resistance
= 1.29 / 520
= 2.48 * 10-3 S cm-1
Therefore, molar conductivity:
Λm = 103 κ / M
= 103 * 2.48 * 10-3/0.02
= 124 S cm2 mol-1