At infinite dilution, equivalent conductances of $Ba^{2+}$ & $Cl^-$ ions are $127$ & $76 ext{ ohm}^{-1} ext

Question

At infinite dilution, equivalent conductances of $Ba^{2+}$ & $Cl^-$ ions are $127$ & $76 	ext{ ohm}^{-1}	ext{cm}^{-1}	ext{ eq}^{-1}$ respectively. Equivalent conductance ($	ext{ohm}^{-1}	ext{cm}^{-1}	ext{ eq}^{-1}$) of $BaCl_2$ at infinite dilution is:

Accepted Answer

According to Kohlrausch's law of independent migration of ions, the equivalent conductance of an electrolyte at infinite dilution is equal to the sum of the equivalent conductances of its constituent ions at infinite dilution.

$\Lambda^{\circ}_{eq}(BaCl_2) = \lambda^{\circ}_{eq}(Ba^{2+}) + \lambda^{\circ}_{eq}(Cl^-)$

Given:
$\lambda^{\circ}_{eq}(Ba^{2+}) = 127 	ext{ ohm}^{-1}	ext{cm}^{-1}	ext{ eq}^{-1}$
$\lambda^{\circ}_{eq}(Cl^-) = 76 	ext{ ohm}^{-1}	ext{cm}^{-1}	ext{ eq}^{-1}$

$\Lambda^{\circ}_{eq}(BaCl_2) = 127 + 76 = 203 	ext{ ohm}^{-1}	ext{cm}^{-1}	ext{ eq}^{-1}$

Note: For equivalent conductance, we simply add the equivalent conductances of the ions. The stoichiometric coefficients are not multiplied as they are in the case of molar conductance.

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