20g of a binary electrolyte (molecular weight = 100) are dissolved in 500g of water. The freezing point of the solution is  −0.744∘ C;   Kf=1.86 K molality−1. The degree of dissociation of electrolyte is

Applying Depression freezing point,ΔTf=iKf×m Where,  ΔTf is the Depression freezing point Kf is m is the molality the Cryoscopic constant  i is the Van’t Hoff factor⇒0.744=i×1.86×20100×1000500⇒i=5×0.7441.80×2=1∴α=1−in−1=1−12−1=01=0