How does a insoluble impurity affect the boiling point temperature of a liquid?
Insoluble impurities (like sand in water) do not affect the boiling point temperature of a liquid at all. Raoult’s Law is commonly used to describe the effect of impurities on boiling point temperature. Simply put, Raoult’s Law states that the vapor pressure of an ideal solution is equal to the sum of partial vapor pressures of each component in the solution. The partial vapor pressure of a component in an ideal solution is that component’s mole fraction times it’s vapor pressure, as a pure compound, at the solution’s temperature. What this means is that If a soluble impurity has a lower normal boiling point than the main liquid, then the boiling point of the mixture drops…this is what happens with mixtures of ethanol and water. Conversely, if a soluble impurity has a higher boiling point than the main liquid, then the boiling point rises…this is what happens when adding salt or ethylene glycol (antifreeze) to water. However, since an INSOLUBLE impurity does not change the mole fra
