Phenol associates in benzene to certain extent to form a dimer. A solution containing `20 xx 10^(-3) kg` of phenol in `1.0 kg` of benzene hs its freezing point depressed by `0.69 K`. Calculate the fraction of phenol that has dimerized. (`K_(f)` for benzene is `5.12 K kg mol^(-1)`).

Explanation

Total=`1-alpha+(alpha/2)=1-(alpha/2)`
`i=(1-(alpha//2))/1=1-alpha/2`
`DeltaT_(f)=iK_(f)(W_(2)xx1000)/(Mx_(2) xx W_(1))`
`0.69=(i xx 5.12 xx 20 xx 10^(3))/ (94 xx 1.0 kg)`