Question

Imagine two solutions with the same concentration and the same boiling point.?
Imagine two solutions with the same concentration and the same boiling point, but one has ethanol as the solvent and the other has carbon tetrachloride as the solvent. Determine that concentration and boiling point.

ethanol: 78.4 Celsius 1.22 c/m

carbon tetrachloride: 76.8 Celsius 5.03 c/m

Answer 1

The boiling points are 1.6 degrees apart; i.e., 78.4-76.8 = 1.6 so the CCl4 must increase 1.6 more than the ethanol.If you want the boiling point to be the same, that means you want
[1.22*m + 1.6] = 5.03*m
and solve for m = about 0.42. We can check that out from dT = Kb*m
dTethanol = 1.22*0.42 = 0.51 so b.p. = 78.4 + 0.51 = 78.9

dTCCl4 = 5.03*0.42 = 2.1 so b.p. = 76.8 + 2.1 = 78.9 and voila, the b.p. are the same. The concns are, or course, 0.42 m.

Answer 2

works