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.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(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: $\text{Acetic acid} < \text{Trichloroacetic acid} < \text{Trifluoroacetic acid}$.

Explore More

Similar Questions

An aqueous solution contains $5\%$ by weight of urea and $10\%$ by weight of glucose. The freezing point of the solution is .......... $^oC$. [ $K_f$ for $H_2O$ is $1.86 \ K \ kg \ mol^{-1}$ ]

$5 \ g$ sucrose (molar mass $= 342 \ g \ mol^{-1}$) is dissolved in $100 \ g$ of solvent,decreasing the freezing point by $2.15 \ K$. What is the cryoscopic constant $(K_{f})$ of the solvent?

What is observed during the depression of freezing point?

$A$ fixed amount of glucose is dissolved in $100 \text{ g}$ water to form a solution that freezes at $-0.2^\circ\text{C}$. If the solution is cooled down to $-0.25^\circ\text{C}$, then ......... $\text{g}$ of ice would have separated.

What is the depression of freezing point,when mole fraction of non-electrolyte solute in aqueous solution is $0.01$ (in $K$)? ($K_f$ of $H_2O = 1.86 \ K \ kg \ mol^{-1}$)

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo