1 g of a monobasic acid when dissolved in 100 g of water lowers the freezing point by 0.168^(@)C.0.2g of the same acid when dissolved and titrated required 15.1 mL of N/10 alkali solution. Calculate the degree of dissociation of the acid.

1 g of a monobasic acid when dissolved in 100 g of water lowers the fr

1.	1 g of a monobasic acid when dissolved in 100 g of water lowers the freezing point by 0.168^(@)C.0.2g of the same acid when dissolved and titrated required 15.1 mL of N/10 alkali solution. Calculate the degree of dissociation of the acid.
Answer» Solution :Observed MOLECULAR mass of the acid. `M_(2)=(1000K_(f)w_(2))/(w_(1)DeltaT_(f))=(1000xx1.86xx1)/(100xx0.168)=110.71` `"15.1 mL of "(N)/(10)" alkali neutrilize acid = 0.2 g"` `therefore " 1000 mL of 1 N alkali will neutralize acid "=(0.2)/(15.1)xx1000xx10=132.45g` This is the normal (calculated) molecular mass of the acid. `therefore""i=("Normal molecular mass")/("Observed molecular mass")=(132.45)/(110.71)=1.196` `{:(,HA,hArr,H^(+),+,A^(-),),("Initial",1,,0,,0,),("After disso.",""1-ALPHA,,alpha,,alpha",","Total "=1+alpha):}` `i=1+alpha"or"alpha=i-1=1.196-1=0.196=19.6%`