On mixing urea, the boiling point of $H_{2}O$ changed to $100.5^{\circ}C$. Calculate the freezing point of the solution, if $K_{f}$ of water is $1.87 \ K \cdot kg \cdot mol^{-1}$ and $K_{b}$ of water is $0.52 \ K \cdot kg \cdot mol^{-1}$. (in $^{\circ}C$)

Which of the following pairs of solutions is isotonic?
$A$. $18 \ g/L$ of glucose solution and $6 \ g/L$ of urea solution
$B$. $10 \ g/L$ of glucose solution and $10 \ g/L$ of urea solution
$C$. $0.01 \ M \ NaOH$ solution and $0.02 \ M$ glucose solution
$D$. $0.01 \ M \ NaCl$ solution and $0.01 \ M$ glucose solution
(Assume that $NaCl$ undergoes complete dissociation)

Which one of the following statements is false?

$A$ solution of urea (molar mass $60 \, g \, mol^{-1}$) boils at $100.18 \, ^oC$ at atmospheric pressure. If $K_f$ and $K_b$ for water are $1.86$ and $0.512 \, K \, kg \, mol^{-1}$ respectively,the above solution will freeze at ........... $^oC$.

If a $1 \ m$ solution of benzoic acid in benzene has a freezing point depression of $2.56 \ ^{\circ}C$ $(K_f = 5.12 \ ^{\circ}C \ kg \ mol^{-1})$ and a boiling point elevation of $2.53 \ ^{\circ}C$ $(K_b = 2.53 \ ^{\circ}C \ kg \ mol^{-1})$,select the correct statement$(s)$:
Statement $I$: There is dimer formation when undergoing freezing.
Statement $II$: There is no change when undergoing boiling.
Statement $III$: Reverse of $I$ and $II$.
Statement $IV$: Dimer formation in freezing and boiling state.

For a dilute solution containing $2.5 \ g$ of a non-volatile non-electrolyte solute in $100 \ g$ of water,the elevation in boiling point at $1 \ atm$ pressure is $2 \ ^\circ C$. Assuming the amount of solute is much lower than the amount of solvent,the vapour pressure $(mm \ Hg)$ of the solution is: (take $K_b = 0.76 \ K \ kg \ mol^{-1}$)