Question

Derive a relationship between molar conductivity and equivalent conductivity.

Write expressions showing the mutual relationship between equivalent and molar conductivities.

Answer 1

A relationship between molar conductivity (Λ_m) and equivalent conductivity (Λ_eq) can be obtained with the help of the following equations:

`Lambda_(eq) = kappa xx 1000/N`    ...(i)

`Lambda_m = kappa xx 1000/M`    ...(ii)

Dividing equation (ii) by equation (i), we get

`Lambda_m/Lambda_(eq) = (kappa xx 1000/M)/(kappa xx 1000/N)`

`Lambda_m/Lambda_(eq) = N/M`

= `"No. of gram equivalents of electrolyte"/"No. of moles of electrolyte"`

or, `Lambda_m/Lambda_(eq) = ("Mass of electrolyte"/"Equivalent mass")/("Mass of electrolyte"/"Molar mass")`

= `"Molar mass"/"Equivalent mass"`

∴ `Lambda_m = ("Molar mass"/"Equivalent mass") xx Lambda_(eq)`