Calculate the boiling point of a solution prepared by adding 15 g of NaCl to 250 g of water(Kb for water + 0.512 K kg mol-1, Molar mass mas of NaCl = 58.44 g)
Moles of NaCl = 15/58.44
= 0.25 moles of NaCL
Kg of solvent = 250/1000 Kg
= 0.25 Kg of water
Therefore, Molality:
= 0.25/0.25
= 1 molal
For water change in BP:
ΔTb = Kb * m
= 0.52 * 1
= 0.52 K
Since water boils at 373.15 K at 1.013 bar pressure, therefore the boiling of solution will be 373.15+0.52 = 373.67 K