The vapour pressure of water at room temperature is 23.8 mm Hg. The vapour pressure of an aqueous solution of sucrose with mole fraction 0.1 is equal to :

Given, P^o = vapour pressure of pure solvent=23.8 mm of Hg

P_s =  vapour pressure of solution

m= mole fraction of solute=0.1

$$\begin{gathered} \frac{{\mathrm{P}}^{\mathrm{o}}-{\mathrm{P}}_{\mathrm{s}}}{{\mathrm{P}}^{\mathrm{o}}}={\mathrm{X}}_{\mathrm{s}} \\ \frac{23.8-{\mathrm{P}}_{\mathrm{s}}}{23.8}=0.1 \\ {\mathrm{P}}_{\mathrm{s}}=21.42 \mathrm{mm} \mathrm{of} \mathrm{Hg} \end{gathered}$$

Hence, the correct option (C). 21.42 mm Hg