What is meant by positive deviations from Raoult's law ? Give an example. What is the sign of `Delta_(mix)H` for positive deviation ?

Explanation

If the vapour pressure of a solution is higher than what is expected from Raoult.s law, it is called positive deviation from Raoult.s law. A mixture of ethanol and acetone shows positive deviation from Raoult.s law. Sign of `Delta_(mix) H` for such deviation is + ve i.e., it is endothermic.