Hach BioTector B3500C, Руководство пользователя

Страница: 67 / 165

Page 67
Control of Normality:
In order to check the Normality of the acid solution prepared, take a 12 ml sample from the prepared 6.0 N
sulfuric acid solution. Add 2-3 drops phenolphthalein and just enough 1.2 N sodium hydroxide until the color
of the mix becomes red. If the normality is correct, 60 ml of 1.2 N sodium hydroxide will neutralize 12 ml of 6.0
N sulfuric acid.
Calculations for Different Purities of Sulfuric Acid:
Table 7 below tabulates the required amounts of sulfuric acid at different purities.
Table 7 Amounts of concentrated sulfuric acid required to prepare 25 liters of 6.0 N acid solutions at
various purities.
% Purity of Sulfuric Acid
Sulphuric Acid
quantity per 25 Liter container
(grams)
100 7356
99 7430
98 7505
97 7583
96 7662