State and explain Kohlrausch's law of independent migration of ions. The equivalent conductance at infinite dilution ∧ eq ∞ for sodium acetate, sodium chloride, and hydrochloric acid are 78 , 109 and 384 Ohm - 1 cm 2 g . eq - 1 respectively. Calculate ∧ eq ∞ acetic acid.

The individual contribution of an ion towards the total equivalent conductivity of the electrolyte is called the equivalent ionic conductivity. On the basis of this, Kohlrausch's gave a law that is known as Kolrausch's law of independent migration of ions. According to this law, the equivalent conductance of an electrolyte at infinite dilution can be expressed as the sum of the equivalent conductance of cations and anions at infinite dilution. For example, the equivalent conductance of sodium chloride NaCl at infinite dilution is equal to the sum of the equivalent conductance of sodium ion and chloride ion at infinite dilution. This can be expressed as: ∧ eq NaCl ∞ = λ Na + ∞ + λ Cl - ∞ Given: The equivalent conductance of sodium chloride at infinite dilution ∧ eq NaCl ∞ = 109 Ohm - 1 cm 2 g . eq - 1 The equivalent conductance of sodium acetate at infinite dilution ∧ eq CH 3 COONa ∞ = 78 Ohm - 1 cm 2 g . eq - 1 The equivalent conductance of Hydrochloric acid at infinite dilution ∧ eq HCl ∞ = 384 Ohm - 1 cm 2 g . eq - 1 According to Kolrausch's law, the equivalent conductance of a weak electrolyte can be determined by the help of the equivalent conductivities of strong electrolytes. So, ∧ eq CH 3 COOH ∞ = ∧ eq CH 3 COONa ∞ + ∧ eq HCl ∞ - ∧ eq NaCl ∞ = 78 + 384 - 109 = 353 S cm 2 g . eq - 1 Hence, the equivalent conductance of acetic acid at infinite dilution is 353 S cm 2 g . eq - 1 .