The organic analysis of potable waters / by J. A. Blair.

  • Blair, J. A. (James Andrew)
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: The organic analysis of potable waters / by J. A. Blair. Source: Wellcome Collection.

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    violently unless this precaution be taken. When the liquid is heated to nearly the boiling-point, it is allowed to flow backwards and forwards between the receiver and retort, shaking the contents well from time to time. This operation ensures that all the chlorine is absorbed by the liquid and acts on the ferrous sulphate, producing ferric salt and hydro- chloric acid. At the end of five minutes the reaction may be considered completed, and all chlorine con- verted into hydrochloric acid or ferrous chloride. It only remains to boil off the carbonic acid into a solution of barium hydrate, and estimate the carbonic acid. For this purpose, the 6 oz. flask, fitted with the rubber tubing, is partly filled with distilled water— the bottom of the flask should be covered with about half an inch of water—and the water boiled till all air be expelled from the flask; then clip the rubber tubing in the usual way. When the flask has cooled, run in 10 c.c. of the solution of barium hydrate, by means of a pipette, in the same manner as when the ferrous sulphate was passed into the receiver. It is essential to get the whole of the baryta solution into the flask, so the pipette must be allowed to empty itself till only a few drops of the solution be left in it; then clip the tubing and quickly withdraw the pipette from the tubing, when the remaining few drops of the solution will be sucked out of the pipette into the rubber