The purpose of experiment seven is to construct a boiling point composition diagram for a mixture of propane 1-all and water in order to determine the composition and boiling point of the azeotropic mixture. The first step is to set up the apparatus as shown. Turn on the condenser water. Place approximately 95 ml of propane 1-all and a stirring bar into the 3-neck boiling flask. Make sure all the joints in the glassware are closed. Slowly turn on the magnetic stirrer. Start the distillation by setting the real stat initially at 70. This value can be adjusted as required. Boil and distill gently. The rated distillation should be about 1 drop per second, which can be achieved by adjusting both the real stat and the height of the lab jack. Collect the distillate into a 250 ml early-mire flask. Record the temperature to one decimal place when the temperature becomes constant. Lower the heating mantle, return the distillate to the boiling flask and add 3 ml of water. Raise the heating mantle and bring the solution to a gentle boil. After 3 drops of past into the early-mire flask, collect sample 1D and record the boiling temperature during the collection. Collect only enough sample to measure its refractive index. Stopper the sample flask without delay. Immediately lower the heating mantle and collect sample 1R by removing one of the stoppers on the round bottom flask. Insert a pasture pipette, pump it 3 times, withdraw the sample and deliver it into the sample flask. Stopper the flask. Add the next aliquot of water and repeat until all of the samples have been collected. Use the same procedure to collect the data for the water-rich side of the diagram.