Chapter 3 Electrochemistry, Chemistry class 12 Chapter 3 Electrochemistry Chemistry, Class 12 | Page 16

Molar conductivity
Variation of Conductivity and Molar Conductivity with Concentration
Molar conductivity
o
It is denoted by the symbol . It is related to the conductivity of the solution by the following equation :
o The units of is S m 2 mol -1 .
Problem :
THE CONDUCTIVITY OF 0.20 M SOLUTION OF KCL AT 298 K IS 0.0248 SCM -1 . CALCULATE ITS MOLAR CONDUCTIVITY .
Solution : k = 0.0248 S cm - 1 c = 0.20 M Molar conductivity , Λm = ( k x 1000 ) / c
= 0.0248 x1000 / 0.20 = 124 Scm 2 mol - 1
Variation of Conductivity and Molar Conductivity with Concentration
o
They depend on the concentration of the electrolyte . The Conductivity and Molar Conductivity of both weak and strong electrolytes decreases with decrease in concentration as the number of ions per unit volume carrying the current in a solution decreases on dilution .