pure benzene freezes at `5.3^(@)C`. A solution of 0.233 g of phenyl acetic acid `(C_(6)H_(5)CH_(2)COOH)` freezes at `4.47^(@)C`. Form this observation
pure benzene freezes at `5.3^(@)C`. A solution of 0.233 g of phenyl acetic acid `(C_(6)H_(5)CH_(2)COOH)` freezes at `4.47^(@)C`. Form this observation, one can conclude that pbenyl acetic acid
A. exists as such in benzene
B. undergoes partial ionisation in benzene.
C. undergoes complete ionisation in benzene
D. dimerises in benzene.
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Correct Answer - d
`DeltaT_(f)=5.3-4.47=0.83 K`
`"Molaliy (m)"=((0.223 g)//(0.0044 kg))/((136 g mol^(-1)))`
`=0.373 mol//kg`
`DeltaT_(f)=iK_(f)m`
`i=(DeltaT_(f))/(K_(f)m)=((0.83K))/((5.12 K mol^(-1))xx(0.373 mol kg^(-1)))`
=0.435.
Since I is close to 0.5, this means that the acid dimerises in benzene.
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