Procedure
Flush a 250-mL iodine flask with nitrogen to expel the air, and insert the stopper in the flask to exclude carbon dioxide. Transfer 50.0 mL of
Barium hydroxide solution and about 600 mg of Propylene Carbonate, accurately weighed, to the flask, and loosely reinsert the stopper. Moisten the stopper with 3 drops of water, and heat the flask on a steam bath for 10 minutes. Remove the flask from the steam bath, add 6 drops of phenolphthalein TS, and titrate while hot with 0.5 N hydrochloric acid VS until only a trace of pink color remains. Perform a blank determination, using the same
Barium hydroxide solution. Each mL of 0.5 N hydrochloric acid consumed is equivalent to 25.52 mg of C
4H
6O
3.