Question

Determine the boiling point of ethylene gylcol - water solution of different composition

Answer 1

Ethylene Glycol is completely miscible in water.  We first find the number of moles of Gycol and number of moles of water in the mixer.  Then we find the molar fraction of Ethylene Glycol.  

We know, from the standard tables ,  the vapour pressures (at equilibrium) of pure Ethylene glycol and pure water at their normal boiling points.  

Using Raoult's law of partial pressures, we find the molar weighted sum of vapour  pressures.  That is the vapour pressure of the mixer.

From the vapour pressure, and using the pressure-boiling point curve for Ethylene Glycol, we find the boiling point.