Question

How can the degree of dissociation of acetic acid be calculated from its molar conductance data?

Answer 1

The degree of dissociation (α) of acetic acid, a weak electrolyte, can be calculated using its molar conductance with the formula:

`alpha = (Lambda_m)/(Lambda_m^0)`

Where,

Λ_m = molar conductivity at a given concentration

`Lambda_m^0` = molar conductivity at infinite dilution (when dissociation is complete).

At a certain concentration, acetic acid is only partially ionised, so Λ_m is less than `Lambda_m^0`.

The ratio of the measured molar conductivity to the maximum (infinite dilution) value gives the fraction of molecules dissociated, that is, the degree of dissociation.

This method provides a simple and practical approach for determining α experimentally.