Question

Ethylene glycol, C2H6O2, a nonelectrolyte, is added to the water in a radiator to give a solution containing 0.75 mole of ethylene glycol in 1 kg of water (solvent). What is the boiling point of the solution?

Answer 1

Answer : The boiling point of the solution is
`101.4^oC`

Explanation :

Formula used for Elevation in boiling point :

`\Delta T_b=i* k_b* m`

or,

`T_b-T^o_b=i* k_b* (n_2)/(w_1)`

where,

`T_b` = boiling point of solution = ?

`T^o_b` = boiling point of water =
`100^oC`

`k_b` = boiling point constant of water =
`1.86^oC/m`

m = molality

i = Van't Hoff factor = 1 (for non-electrolyte)

`n_2` = moles of solute (ethylene glycol) = 0.75 mole

`w_1` = mass of solvent (water) = 1 kg

Now put all the given values in the above formula, we get:

`(T_b-100)^oC=1* (1.86^oC/m)* (0.75mole)/(1kg)`

`T_b=101.4^oC`

Therefore, the boiling point of the solution is
`101.4^oC`