By Raoult's Law PT=PP∘XP+PQ∘XQ PP∘=80 torr XP=53PQ∘=60 torr XQPTPT=52=80×53+60×52=48+24=72 torr. Related Theory Solutes which dissociate or associate in a particular solution will not obey Raoult's law. Raoult's law applies to solutions containing non-volatile solute only. Raoult's law cannot be applied to concentrated solutions.