Analysis of a Mixed Acid

Analysis of a Mixed Acid.—1. Total Aridity (calculated as H2S04).— About 5 c.cs. of mixed acid are put into a tared weighing bottle and its weight found. This is then washed into a beaker and titrated with N/l caustic soda solution, using methyl orange as indicator. 

H2S04 (Actual).—About 5 c.cs. are weighed out into a tared dish, and heated on a water bath till all the HNOs and HC1 (if any) are driven ofE. This is then washed into a flftsk and titrated, as in 1. 

Total acidity as HaSO4— 1IN03 X = real HaS04. 

HNOs by Nitrometer.—About 5 gins, of mixed acid are weighed out and placed in the funnel of a nitrometer, and washed in with a little pure cone. H2S04. The nitrometer is well shaken until all the NO is evolved. It is then allowed to stand till room temperature is reached, when the temperature and barometric pressure are noted. 

This figure includes HNOa, which also gives NO in the nitrometer. It can be estimated as in 4. 

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D.V.S. Calculations. A typical reported analysis of a mixed acid for preparing nitroglycerine is as follows ... 

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