For precipitation titrations

Table 11.30 lists standard solutions for precipitation titrations and Table 11.31 lists specific reagents as indicators, adsorption indicators, and protective colloids for precipitation titrations. 

The list given below includes the substances that are most used and most useful for the standardization of solutions for precipitation titrations. Primary standard solutions are denoted by the letter (P) in Column 1. 

Acid-base, redox, precipitation and chelometric titrations are usually dealt with in textbooks on analytical chemistry. The titration curves in these titrations can be obtained potentiometrically by use of appropriate indicator electrodes, i.e. a pH-glass electrode or pH-ISFET for acid-base titrations, a platinum electrode for redox titrations, a silver electrode or ISEs for precipitation titrations, and ISEs for... 

End-point detection for precipitation titrations commonly relies on electrodes las in Figure 7-9) or indicators. This section discusses two indicator methods applied to the titration of Cl-with Ag+. Titrations with Ag4 are called argentometric titrations. 

The Student Web Site, www.whfreeman.com/cica7e, has directions for experiments that may be reproduced for your use. At this Web site, you will also find lists of experiments from the Journal of Chemical Education, a few downloadable Excel spreadsheets, and a few Living Graph Java applets that allow students to manipulate graphs by altering data points and variables. Supplementary topics at the Web site include spreadsheets for precipitation titrations, microequilibrium constants, spreadsheets for redox titration curves, and analysis of variance. 

Anodically generated silver ions can be used for precipitation titrations of various substances. A cell constructed from a piece of heavy silver wire can be used. Substances precipitated include Cr, Br , D, and mercaptans. Similar applications using mercury(I)... 

Effect of complexation on solubihty (key equations 11.10, 11.11), p. 345 Calculating precipitation titration curves, p. 346 Indicators for precipitation titrations, p. 349... 

A typical experimental arrangement for precipitation titrations is shown in Figure 19.15. After each addition of titrant and attainment of equilibrium, an aliquot of the supernatant is drawn into the counting chamber and its activity measured. The solution is then ejected back into the titration vessel, and the next addition of titrant is made. 

Electrodes for precipitation titrations The choice of the electrode depends on the character and properties of ions taking part in the titration reaction. Common... 

A selection of indicators for precipitation titrations is given in Table 3. 

Non-aqueous or partially aqueous systems are also preferred for precipitation titrations in order to lower the solubility of the resulting precipitate. Lower detection limits and more easily evaluated titration curves are thus obtained. The electrodes described here usually have electrical resistances less than 1 MOhm. This allows them to be used in cooled solutions (this resistance often has an exponential temperature dependence), which sometimes also lowers the solubility by a factor of 2 or 3 and thus extends the detection limit. 

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