Question

Water has Kb=0.52k kg per mole& Kf=1.8k kg per mole. A solution boils at 100.26c what shall be it's freezing point?

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Answer 1

m = 1000Kb×w/W×?T

Given, Kb = 2.67, w = 2.5 g, W = 100 g, T = 0.42    

m = 1000×2.67×2.5/100×0.42 = 158.9

The molecular mass of substance is 158.9.