Question

2.7 Kg of each of water and acetic acid are mixed, The freezing point of the solution will be \(-x ^\circ C.\) Consider the acetic acid does not dimerise in water, nor dissociates in water x = ______(nearest integer)

[Given : Molar mass of water = 18 g \(mol ^{-1}\), acetic acid = 60 g \(mol ^{-1}\)]

 \(^{K_f} H_2O : 1.86 \,K\,kg \,mol ^{-1}\)

\(^{K_f} \text{acetic acid} : 3.90 \,K \, kg \, mol ^{-1}\)

freezing point : \(H_2O\) = 273 K, acetic acid = 290 K]

Answer 1

Correct answer is : 31

As moles of water > moles of \(CH_3COOH\)

water is solvent.

\(\mathrm{T}_{\mathrm{F}}^{\circ}-\left(\mathrm{T}_{\mathrm{F}}\right)_{\mathrm{S}}=\mathrm{K}_{\mathrm{F}} \times \mathrm{M}\)

\(0-\left(\mathrm{T}_{\mathrm{F}}\right)_{\mathrm{S}}=1.86 \times \frac{2700 / 60}{2700 / 1000} \)

\(\left(\mathrm{~T}_{\mathrm{F}}\right)_{\mathrm{S}}=-31^{\circ} \mathrm{C}\)