Standard methods for the examination of water and sewage

by American Public Health Association. Laboratory Section; American Chemical Society; Association of Official Agricultural Chemists

8. Phenolphthalein indicator. See page [36].

9. Bromine water.

10. Stannous chloride, N/20. This should be frequently standardized by titration against a standard iron solution. One cc. of N/20 stannous chloride is equal to 0.0028 gram of iron (Fe) estimated in the ferrous state.

11. Sodium hydroxide, N/1. Free from carbonate. This should be frequently standardized by titration against a standard acid solution in presence of phenolphthalein indicator. One cc. of N/1 sodium hydroxide is equal to 0.049 gram of sulfuric acid (H₂SO₄), or to 0.03645 gram of hydrochloric acid (HCl).

12. Sodium hydroxide, N/20. Free from carbonate.

13. Standard potassium permanganate. A N/10 solution. One cc. of N/10 potassium permanganate is equal to 0.0056 gram of iron (Fe) estimated in the ferrous state.

14. Alcohol. Ethyl alcohol, 95 per cent.

15. Sugar. Solid granulated cane sugar.

SULFATE OF ALUMINIUM.

Determine and report insoluble matter, aluminium oxide (Al₂O₃), ferric oxide (Fe₂O₃), ferrous oxide (FeO), basicity ratio, and, if present, free acid as H₂SO₄. If the material is what is known as “granular” sulfate mix it well before sampling. If it is in lump form crush it to ⅛ to ¼ inch size, mix, and sample it. It is unnecessary to grind the sample to a fine powder, but it is preferable to have the particles fairly uniform in size.