The freezing point of benzene decreases by `0.45^(@)C` when `0.2 g` of acetic acid is added to `20 g` of benzene. IF acetic acid associates to form a dimer in benzene, percentage association of acetic acid in benzene will be
`(K_(f) "for benzene" = 5.12 K kg mol^(-1))`

Options

A. `94.6`%
B. 0.646
C. 0.804
D. 0.746

Explanation

`DeltaT_(f)=I xx K_(f)xxmimplies 0.45=9xx5.12xx0.2/60xx1000/20`
`i=0.527`
`underset(1-alpha)(2 A COH)+underset(alpha//2)((ACOH)_(2))`
`i=1-(alpha)/2implies0.527=1-(alpha)/2impliesalpha=0.946` or 94.6%