`72.5g` of phenol is dissolved in 1kg of a solvent `(k_(f) = 14)` which leads to dimerization of phenol and freezing point is lowered by 7 kelvin. What percent of total phenol is present in dimeric form?

Answer

`70%`

Explanation

`{:(underset(0.77mol)(2PhOh),hArr,underset(-)((PhOH)_(2))),(0.77(1-prop),,0.77prop//2):}`
`I = 1 - prop //2`
`DeltaT_(f) = iK_(f) m`
`7 = (1-prop) xx 14 xx (72.5//94)/(1)`
`0.649 = 1 - prop //2`
`prop//2 = 0.35`
`prop = 0.70`
% of phenol in dimeric form
`=(0.77 prop//2)/(0.77) xx 100 = (prop)/(2) xx 100 = 35%`