Where ∆Tb=Tb∘−Tb =100−98.98=1.02 Kb= molal elevation or ebullioscopic constant w= weight of the solute M= molar mass of solute W= weight of solvent (in grams) Now, ∆Tb=
0.51×w×1000
60×2
1.02=
0.51×w×1000
120
w=
1.02×120
0.51×1000
=
122.4
510
=0.24 or w=240g So, 240g of urea is to be added to 2kg of water to get the boiling point 100∘C at same place.