Answer to Question #55941 in General Chemistry for Lia

Question

During the distillation of a mixture of two miscible liquids with very different boiling points, the temperature rises to a constant reading and before returning to a higher reading. Explain the likely cause of this fluctuation in temperature readings.then drops off

Answer 1

Upon heating of the mixture the liquid with lower boiling point is distillated first. Its vapors goes up and heats the thermometer, therefore, the first constant reading is observed. Then, when this liquid is finished, the temperature rises to the boiling point of the second substance. The reading remains constant, unless the larger part of the second substance is distillated. After this the temperature reading falls down because there are almost no more vapors of the second liquid which heats the thermometer.