kohlrausch’s law of independent migration of ions:

kohlrausch’s law of independent migration of ions:
kohlrausch studied the molar or equivalent conductivities at infinite dilution ?o for a number of pairs of strong electrolytes each having a common cation or anion.
Then, Kohlrausch calculated the differences of ?o values of each pair. A few of these results are given in the table below :
??o
?o?-1.cm2 electrolyte ??o
?o ?-1.cm2 Electrolyte
2.06 151.92
149.86 KBr
KCl 23.41 149.86
126.45 KCl
NaCl
2.06 128.51
126.45 NaBr
NaCl 23.41 151.92
128.51 KBr
NaBr
2.06 117.09
115.03 LiBr
LiCl 23.41 144.96
121.55


We find that ??o values for each pair of Na & K salts having a common anion is same, irrespective of the anion.
Similarly, the ??o values for each pair of salts having the same different anions and a common cation is same, irrespective of the cation.

Based on this, Kohlrausch concluded that :
Each ion makes a definite contribution to the total molar or an equivalent conductivity of an electrolyte at infinite dilution, irrespective of the nature of the other ion of the electrolyte.
This individual contribution of an ion towards the total molar conductivity is called molar ionic conductivity.