TOTAL HARDNESS BY SODA REAGENT METHOD.[47][74][81][94d]

Add standard sulfuric acid to 200 cc. of the sample until the alkalinity

is neutralized. (See Procedure with methyl orange, p. 37.) Then apply

the non-carbonate hardness method (pp. 34–35). This method gives fairly

satisfactory estimates of total hardness of hard waters.

Standard methods for the examination of water and sewage · 第 60 / 249 题