Hanna-instruments HI 904 Uživatelský manuál stáhnout pdf (Strana 162)

TITRATION THEORY

Figure 3.

Figure 4.

Figure 3 shows a traditional titration curve. The curve is obtained by plotting the pH value

against the volume of NaOH added.

2.2.3 Argentometric Titrations

Argentometric titrations use silver (nitrate) as the titrant and are generally precipitation

titrations, as many silver salts are insoluble. These titrations are commonly used to titrate

and determine the concentration of bromide, chloride, cyanide, iodide, and sulfide.

Argentometric titrations can be done with Mohr’s indicator, when all of the chloride has

reacted, a red silver chromate precipitate is formed or the titration can be easily followed

with a silver ISE (or chloride ISE for chloride titrations) and a reference electrode.

Figure 4 shows the titration of 50 mL of 0.1N NaCl with 0.1N AgNO

. The potentiometric

signal is from a chloride ISE, and is plotted as pCl (- log [Cl

]).

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Hanna-instruments HI 904 Uživatelský manuál Strana 162