Question

the boiling point of pure solvent is 353.23K . when 1.2g of a non-volatile solute was dissolved in 60g of a pure solvent. theboiling point raised to 354.11K. calculate the molar mass of the solute. (Kb for solvent is 3.13Kkg/mol)?​

Answer 1

Explanation:

) The elevation in the boiling point ΔT

b

=354.11−353.23=0.88 K.

The expression for the molar mass of the solute is

M

2

=

ΔT

b

×w

1

K

b

×w

2

×1000

Substitute values in the above expression.

M

2

=

0.88×90

2.53×1.8×1000

=57.5 g/mol

Hence, the molar mass of the solute is 57.5 g/mol

b) i. Molality is the number of moles of solute dissolved in 1kg of solvent.

Molality =

Volume of solvent (in kg)

Number of moles of solute

ii. Two solutions are isotonic if they have the same osmotic pressure at a given temperature.