1.0 gram of a monobasic acid HA in 100 gram H ₂ O lower the freezing point by 0.155 K .0 .45 gram of same acid require 15 ml of 1 5 M KOH solution for complete neutralisation. If the degree of dissociation of acid is , then value of ' 20 ' is : ( K _ f . for . H ₂ O =1.86 ~K . Kg / mole )

Step-by-step solution

aligned T_F= & K_F m= & =K_F [ W_ acid 1000 M_ acid H ₂ O ] (M_ acid )_ exp & =120 aligned Also N ₁ ~V ₁= N ₂ ~V ₂ aligned & 0.45 ( M _ acid )_ thor = 1 5 15 1 1000 & & ( M _ acid )_ thor = 0.45 5 1000 15 =150 & & i = ( M _ thor M _ exp )= 150 120 =1.25 & & array l =( i -1)=1.25-1=0.25 . 20 =5 array aligned