Depression in freezing point of 0.1 molal solution of HF is `-0.201^(@)C`. Calculate percentage degree of dissociation of HF. `(K_(f)=1.86 K kg mol^(-1))`.

Explanation

We know
`DeltaT=ixxK_(f)xxm`
`0.201=ixx1.86xx0.1`
`i=1.0806`
The degree of dissociation HF may be calculated as
`alpha=(i-1)/(n-1)=(1.0806-1)/(2-1)=0.0806`
Percentage dissociation `= alphaxx100=0.0806xx100`
`=8.06`