what is ionic mobility and how it is related to transference number

Dear student 

The ionic mobility (μ) is defined as the velocity attained by an ion moving through a gas under unit electric field.
Ionic mobility or Ionic conductance is the conductivity of a solution containing 1 g ion, at infinite dilution, when two sufficiently large electrodes are placed 1 cm apart.
Ionic mobilities ( λa or λc) ∝ speeds of ions (ua or uc)
Unit of ionic mobility is Ohm–1 cm2 or V–1S-1cm2
Ionic mobility and transport number are related as,
λa or λc = ta or tc × λ∞
Absolute ionic mobilityis the mobility with which the ion moves under unit potential gradient. It's unit is cm sec–1.
Absolute ionic mobility = Ionic mobility/96,500

 

Transference number of an ion is the fraction of the total current that is carried by that ion during electrolysis. Different ions carry different fractions of the current because different ions move at different speeds under the same potential gradient.