Which among the following has highest boiling point?

What is the numerical value of osmotic pressure of 1 M urea solution if numerical value of osmotic pressure of 0.5 M urea solution is ' $x$ '?

Calculate vapour pressure of volatile liquid A at given temperature if mole fraction and vapour pressure of volatile liquid B are 0.4 and 900 mm Hg respectively [ $\mathrm{P}_{\text {total }}=600 \mathrm{~mm} \mathrm{Hg}$ ]

Identify from following the correct set of thermodynamic conditions for a reaction to be nonspontaneous at all temperatures.