Chemistry - Electrochemistry Question with Solution | TestHub

According to Kohlrausch's law of independent migration of ions, the molar conductivity of an electrolyte at infinite dilution is the sum of the limiting molar conductivities of its constituent ions.

${\Lambda }_m^{\circ }({\text{C}}_2{\text{H}}_5\text{COOH})={\Lambda }_m^{\circ }({\text{C}}_2{\text{H}}_5{\text{COO}}^{-})+{\Lambda }_m^{\circ }({\text{H}}^{+})$

This can be obtained by adding and subtracting the appropriate strong electrolytes:

${\Lambda }_m^{\circ }({\text{C}}_2{\text{H}}_5\text{COOH})={\Lambda }_m^{\circ }({\text{C}}_2{\text{H}}_5\text{COONa})+{\Lambda }_m^{\circ }(\text{HCl})-{\Lambda }_m^{\circ }(\text{NaCl})$

Substituting the given values:

${\Lambda }_m^{\circ }({\text{C}}_2{\text{H}}_5\text{COOH})=91+426.16-126.45$

${\Lambda }_m^{\circ }({\text{C}}_2{\text{H}}_5\text{COOH})=517.16-126.45=390.71{\text{ ohm}}^{-1}{\text{cm}}^2$

Answer: $390.71$ ohm${}^{-1}$cm${}^2$