When $0.1 \, m$ $CH_3COOH$ is present in a solvent,it shows an elevation in boiling point of $0.75 \, ^oC$. The acid dissociation constant $(K_a)$ will be: (Given: $K_b = 5 \, K \, kg \, mol^{-1}$)

Which of the following statements is incorrect?

$A$ substance '$X$' $(1.5 \ g)$ dissolved in $150 \ g$ of a solvent '$Y$' (molar mass $= 300 \ g \ mol^{-1}$) led to an elevation of the boiling point by $0.5 \ K$. The relative lowering in the vapour pressure of the solvent '$Y$' is . . . . . . $\times 10^{-2}$. (Nearest integer)
[Given : $K_{b}$ of the solvent $= 5.0 \ K \ kg \ mol^{-1}$]
Assume the solution to be dilute and no association or dissociation of $X$ takes place in solution.

After adding a non-volatile solute, the freezing point of water decreases to $-0.186^{\circ} C$. Calculate $\Delta T_b$ if $K_f = 1.86 \text{ K kg mol}^{-1}$ and $K_b = 0.521 \text{ K kg mol}^{-1}$. (in $\text{ K}$)

$25 \ mL$ of an aqueous solution of $KCl$ was found to require $20 \ mL$ of $1 \ M \ AgNO_3$ solution when titrated using $K_2CrO_4$ as an indicator. What is the depression in freezing point of $KCl$ solution of the given concentration? (Nearest integer). Given: $K_f = 2.0 \ K \ kg \ mol^{-1}$. Assume: $(1)$ $100 \%$ ionization and $(2)$ density of the aqueous solution as $1 \ g \ mL^{-1}$.

An aqueous solution of urea (molar mass $= 60 \ g \ mol^{-1}$) boils at $100.18^o C$ at atmospheric pressure. If $K_f = 1.86 \ K \ kg \ mol^{-1}$ and $K_b = 0.512 \ K \ kg \ mol^{-1}$ for water,then the freezing point of the solution is equal to ..... $^o C$.