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 concentration of solute is much lower than the concentration of solvent, the vapour pressure (in mmHg) of the solution is (take $K_b = 0.76$ K kg mol$^{-1}$)