Considering acetic acid dissociates in water, its dissociation constant is $6.25 \times 10^{-5}$. If $5 \mathrm{~mL}$ of acetic acid is dissolved in $1$ litre water, the solution will freeze at $-\mathrm{x} \times 10^{-2}{ }^{\circ} \mathrm{C}$, provided pure water freezes at $0^{\circ} \mathrm{C}$.
$\mathrm{x}=$ . . . . . . . . . (Nearest integer)
Given : $\left(\mathrm{K}_{\mathrm{r}}\right)_{\text {water }}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$.
density of acetic acid is $1.2 \mathrm{~g} \mathrm{~mol}^{-1}$
molar mass of water $=18 \mathrm{~g} \mathrm{~mol}^{-1}$.
molar mass of acetic acid $=60 \mathrm{~g} \mathrm{~mol}^{-1}$.
density of water $=1 \mathrm{~g} \mathrm{~cm}^{-3}$
Acetic acid dissociates as
$\mathrm{CH}_3 \mathrm{COOH} \rightleftharpoons \mathrm{CH}_3 \mathrm{COO}^{\oplus}+\mathrm{H}^{\oplus}$
