The depression in freezing point of water observed for the same amount of acetic acid,trichloroacetic acid,and trifluoroacetic acid increases in the order given above. Explain briefly.
(N/A) The depression in freezing point $(\Delta T_f)$ is a colligative property,which depends on the number of particles (ions) produced in the solution.
Acetic acid $(CH_3COOH)$,trichloroacetic acid $(CCl_3COOH)$,and trifluoroacetic acid $(CF_3COOH)$ ionize to different extents.
The acidity depends on the electron-withdrawing effect of the substituent attached to the carboxylic group.
Fluorine $(F)$ is more electronegative than Chlorine $(Cl)$,which is more electronegative than Hydrogen $(H)$.
Therefore,the electron-withdrawing inductive effect follows the order: $CF_3 > CCl_3 > CH_3$.
This makes the $O-H$ bond in trifluoroacetic acid the most polar,leading to the highest degree of ionization.
Since trifluoroacetic acid produces the maximum number of ions,it shows the greatest depression in freezing point.
Thus,the order of depression in freezing point is: $\text{Acetic acid} < \text{Trichloroacetic acid} < \text{Trifluoroacetic acid}$.
Acetic acid $(CH_3COOH)$,trichloroacetic acid $(CCl_3COOH)$,and trifluoroacetic acid $(CF_3COOH)$ ionize to different extents.
The acidity depends on the electron-withdrawing effect of the substituent attached to the carboxylic group.
Fluorine $(F)$ is more electronegative than Chlorine $(Cl)$,which is more electronegative than Hydrogen $(H)$.
Therefore,the electron-withdrawing inductive effect follows the order: $CF_3 > CCl_3 > CH_3$.
This makes the $O-H$ bond in trifluoroacetic acid the most polar,leading to the highest degree of ionization.
Since trifluoroacetic acid produces the maximum number of ions,it shows the greatest depression in freezing point.
Thus,the order of depression in freezing point is: $\text{Acetic acid} < \text{Trichloroacetic acid} < \text{Trifluoroacetic acid}$.
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