Question

What is the formula for equivalent conductivity and how is it different from molar conductivity formula?

Answer 1

Equivalent conductivity

• When one gram equivalent of an electrolyte is dissolved in a solution then conducting power of all the ions produced is called equivalent conductivity.
• Formula of equivalent conductivity is as follow:

$\lambda =\frac{k\times 1000}{C}$

Where, $\lambda$ = Equivalent conductivity in $\mathrm{S}{\mathrm{m}}^{-2}(\mathrm{gram}{\mathrm{equi}}^{-1})$

$\mathrm{k}$ = Specific conductance in $\mathrm{S}{\mathrm{m}}^{-1}$

$\mathrm{C}$ = concentration of 1 gram equivalent in $\mathrm{gram}\mathrm{equivalents}\times {\mathrm{m}}^{-3}$

Molar conductivity

• When a mole of electrolyte is dissolved in a solution then the amount of conducting power of ions produced is called molar conductivity.
• The formula of molar conductivity is as follows.

${\lambda }_m=\frac{k\times 1000}{m}$

Where, ${\lambda }_m$ = molar conductivity in $\mathrm{S}{\mathrm{m}}^2{\mathrm{mol}}^{-1}$

$\mathrm{k}$ = Specific conductance in $\mathrm{S}{\mathrm{m}}^{-1}$

$\mathrm{m}$ = molarity

Difference in the formula for equivalent conductivity and molar conductivity

• In the formula of equivalent conductivity, a concentration of 1 gram equivalent is required whereas molarity is required in the formula of molar conductivity.