If molality of a solution is $0.05 \ m$ and elevation in boiling point is $0.16 \ K$,then what is the molal elevation constant of the solvent?

The boiling point of $0.2 \ m$ aqueous urea solution is $....... \ ^oC$. ($K_b$ of water $= 0.52 \ K \ kg \ mol^{-1}$)

Molal elevation constant is the elevation in boiling point produced by

$A$ solution containing $2.5 \times 10^{-3} \ kg$ of a solute dissolved in $75 \times 10^{-3} \ kg$ of water boils at $373.535 \ K$. The molar mass of the solute is $..... \ g \ mol^{-1}$. [nearest integer] (Given: $K_b(H_2O) = 0.52 \ K \ kg \ mol^{-1}$,boiling point of water $= 373.15 \ K$)

Calculate the molal elevation constant $(K_b)$ of a solvent if the boiling point of a $0.12 \ m$ solution is $319.8 \ K$ (Boiling point of pure solvent = $319.5 \ K$).

Which of the following aqueous solutions containing $10 \ g$ of solute in each case has the highest boiling point $(B.P.)$?