Determination of alkalinity

Reagents and materials
a, hydrochloric acid standard titration Sodium lactate: c (HCl) = 0.1mol / L;
b, phenolphthalein indicator solution: 10g / L.
Analysis step
Weigh 1.0g sample, accurate to 0.01g, no carbon dioxide dissolved in 20mL of water, add 1 drop of phenolphthalein indicator solution, the solution should be pink. Add 0.4mL hydrochloric ferrous lactate volumetric solution, pink disappears.
Arsenic (As) determination
1.0g sample weighed to the nearest 0.01g, was dissolved in 25mL water, as the sample solution. Press GB8450 rest of "Gutzeit method". And arsenic (As) 3μg comparison arsenic standard solution.
Heavy metals (as Pb) Determination
1.0g sample weighed to the nearest 0.01g, was dissolved in 25mL water, as the sample solution. Press the remaining provisions of GB8451. And lead (Pb) 10μg of lead standard solution to compare.