1. Measurement of percentage concentration of alkali:
Take alkali of 1 ml, and add demineralized water of 100ml and shake them well, add 3 drops of phenolphthalein indicator, then use 1 mol/L hydrochloric acid standard solution for titration until the solution becomes colorless, record the volume b of the consumed hydrochloric acid standard solution, the calculation is as follows:
b·M×40
NaOH%= ×100%
V·d×103
Where:
A - Showing the volume of HCL standard solution for titration, mL.
M - Showing the molar concentration of HCL for titration - mol/L.
40 - Showing the molar mass of NaOH, g/moL.
V - The selected volume of alkali samples, mL.
d— showing the specific gravity of the alkali sample
2. Measurement of the saltness in alkali :NaCl%
Take 0.2ml alkali sample and inject it in the conical flask, add 100mL demineralized water and hake the solution well. Add 2 drops of phenolphthalein indicator, and use dilute nitric acid to neutralize the solution to colorless . Then use T=1mg/L hydrochloric acid standard solution for titration, until the solution turn into Brownish Red from red, record the consumption volume of AgNO3, the calculation is as follows:
V*a
alkali chlorine root Cl%= ×100%
0.2·d·103
Where:
V - showing the consumed volume of AgNO3 for tritraiton, mL.
a - showing the consumed volume of AgNO3 consumed by chlorine root in the demineralized water, mL
d - indicating the specific gravity of alkali sample, g/mol
According to the percentage content of chlorine root in the alkali, the percentage content of NaCl can be converted:
59.5
NaCl%= ×Cl-%=1.65×Cl-%
36.5