Glass bulbs for weighing acids

Oleum. Fuming sulfuric acid a soln of sulfur trioxide in sulfuric acid used as a sulfating and sulfonating agent. See under Acidity in Acids in Vol 1, A88-R to A90-R Acids Used in Manufacture and Analysis of Explosives in Vol 1, A93-L to A93-R and under Nitration in this Vol For analytical procedures, see under Glass Bulbs for Weighing Acids in Vol 6, G78-R to G79-R... 

In the Kostevitch method a sample of explosive (about O.lg) is introduced into a small glass bulb (volume=ca 3.5cc), resembling in appearance that used for weighing fuming acids, but made from a larger diameter tube in order... 

I-0-I5 gm. of the substance to be examined is weighed into a glass bulb which is then placed in a flask containing loo ml. water. After closing the flask with a stopper the bulb is broken, and the whole allowed to stand for 2-3 hours. 40 ml. N/io iodine solution are added from a burette and then an aqueous solution of sodium hydroxide until the liquid is a clear yellow in colour. After allowing to stand for 15-20 minutes, 2 N hydrochloric acid is added to acidify and to liberate the iodine and excess of the latter is then titrated with decinormal sodium thiosulphate in presence of starch. 

About 2 grams of the oil are weighed in a 100 c.c. flask and treated with 10 or 20 c.c. of N/2-alcoholic potash (usually 10 c.c. suffice, 20 c.c. being used only in cases where 10 c.c. have been shown to be insufficient). The flask is closed with a cork traversed by a glass tube about a metre long or by a small upright bulb condenser, and is then heated for half an hour on a water-bath. After cooling, about 50 c.c. of water and a few drops of alcoholic phenolphthalein solution are added and the excess of alkali titrated with N/2-sulphuric acid. 

---