After developing cryoscopy, Ernst Beckmann tried to apply this law, which led to his development of ebulliometry. Despite it not being very practical, it can be used to determine the molecular weight of dissolved substances. Famously discovered in studies of French wine in 1882, it only holds true in dilute solutions, although some "perfect solutions" obey it even at different concentrations. Azeotropes deviate from this law in both positive and negative directions. For 10 points, identify this chemical law that says the partial vapor pressure 
After developing cryoscopy, Ernst Beckmann tried to apply this law, which led to his development of ebulliometry. Despite it not being very practical, it can be used to determine the molecular weight of dissolved substances. Famously discovered in studies of French wine in 1882, it only holds true in dilute solutions, although some "perfect solutions" obey it even at different concentrations. Azeotropes deviate from this law in both positive and negative directions. For 10 points, identify this chemical law that says the partial vapor pressure of a solvent is proportional to its mole fraction.
After developing cryoscopy, Ernst Beckmann tried to apply this law, which led to his development of ebulliometry.
{Raoult}’s law