Question

Find the molality of solution if boiling point increases by 1.75 K and molal elevation constant of solvent is 5K kg mol^-1.

Options

• 0.70 m

• 0.81 m

• 0.35 m

• 0.55 m

Answer 1

0.35 m

Explanation:

The molal elevation in boiling point and molality is related by

`Delta "T"_"b" = "K"_"b" xx "m"`

where, `Delta "T"_"b"` = increase in boilling point

K_b = molal elevation constant

m = molality

`1.75 = 5 xx "m"`

`=> "m" = 1.75/5 = 0.35`