Solid Lead nitrate is dissolved in \( 1 \) litre of water. The solution was found to boil at \( 100.15^\circ \mathrm{C} \). When \( 0.2 \) mol of \( \mathrm{NaCl} \) is added to the resulting solution, it was observed that the solution froze at \( -0.8^\circ \mathrm{C} \). the solubility product of \( \mathrm{PbCl_2} \) formed is __________ \( \times 10^{-6} \) at \( 298 \, \mathrm{K} \). (Nearest integer)
Given : \( K_b = 0.5 \, \mathrm{K \, kg \, mol^{-1}} \) and \( K_f = 1.8 \, \mathrm{K \, kg \, mol^{-1}} \). Assume molality to be equal to molarity in all cases.