A substance 'X' (\( 1.5 \, \text{g} \)) dissolved in \( 150 \, \text{g} \) of a solvent 'Y' (molar mass \( = 300 \, \text{g mol}^{-1} \)) led to an elevation of the boiling point by \( 0.5 \, \text{K} \). The relative lowering in the vapor pressure of the solvent 'Y' is _____ \( \times 10^{-2} \). (nearest integer)
[Given: \( K_b \) of the solvent \( = 5.0 \, \text{K kg mol}^{-1} \) ]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.