You mix AgNO3 and KI in the following molar ratioFixed layer of the electrical double layer migrates to cathode in

I. AgNO31+K1I⟶AgI↓+KNO3Being in equal stoichiometric ratio, Agl is precipitated. It carries no charge and, hence no migrationII. AgNO31+KI2⟶AgI+KNO3KI is in excess hence Agl adsorbs common ion of KI (ie. I-) AgI+KI⟶[AgI]I−⋮K+             Fixed layer Mobile layerFixed layer carries negative charge and moves to anode plate.III. AgNO2 +KI1⟶AgI+KNO3Agl is precipitated and AgNO3 being in excess, Ag+ is adsorbed on AgI.AgI+AgNO3⟶[AgI]Ag+    :   NO3−                       Fixed layer     Mobile layerFixed layer carries positive charge and migrates to cathode (-ve) plate.