Question

a solution must be at a higher temperature than a pure solvent to boil. what colligative property can be employed to achieve this?

Answer 1

Boiling-point elavation.

Answer 2

Answer : The colligative property employed to achieve this can be, Elevation in boiling point.

Explanation :

Elevation in boiling point : It is defined as the temperature or boiling point of a liquid (a solvent) will be higher when the another compound is added. This means that a solution must be at a higher temperature or boiling point than a pure solvent.

For example : When a non-volatile solute (a salt) is added to a pure solvent such as water.

The formula for elevation in boiling point will be,

$\Delta T_b=k_b\times m$

or,

$T_b-T^o_b=\frac{1000\times k_b\times w_2}{w_1\times M_2}$

where,

$T_b$ = boiling point of solution

$T^o_b$ = boiling point of pure solvent

$k_b$ = boiling point constant

m = molality

$w_2$ = mass of solute

$w_1$ = mass of solvent

$M_2$ = molar mass of solute

Hence, the colligative property employed to achieve this can be, Elevation in boiling point.