Solid Lead nitrate is dissolved in 1 litre of water. The solution was found to boil at 100 . 15 ° C . When 0 . 2 mol of NaCl is added to the resulting solution, it was observed that the solution froze at - 0 . 8 ° C . The solutbility product of PbCl 2 formed is _____ × 10 - 6 at 298 K . (Nearest integer) Given : K b = 0 . 5 K kg mol - 1 and K f = 1 . 8 kg mol - 1 . Assume molality to be equal to molari

Step-by-step solution

Let a mole Pb NO 3 2 be added, dissociation of lead nitrate will result in: Pb NO 3 2 → Pb 2 + + 2 NO 3 - a   a   2 a ∆ T b = 0 . 15 = 0 . 5 3 a ⇒ a   =   0 . 1   Pb aq 2 + + 2 Cl aq - → PbCl 2 s During reformation of lead nitrate as a precipitate, Pb aq 2 + + 2 Cl aq - → PbCl 2 s t = 0   0 . 1   0 . 2 t = ∞   0 . 1           0 . 2 - 2 x ....(i) In final solution after addition of 0.2 moles of sodium and chloride io