Chloride argentometric determination

Sodium chromate can serve as an indicator for the argentometric determination of chloride, bromide, and cyanide ions by reacting with silver ion to form a brick-red silver chromate (Ag2Cr04) precipitate in the equivalence-point region. The silver ion concentration at chemical equivalence in the titration of chloride with silver ions is given by... 

The argentometric determination involving titration against AgN03 is carried out in neutral or slightly alkaline media (pH 6.5-10.5). The end point is indicated visually with formation of the red-brown precipitate of Ag2Cr04 which is more soluble than the precipitate of AgCl, or po-tentiometrically (silver indication electrode, calomel reference electrode). The method is used for the determination of chlorides at concentrations > 4 mg F [13, 14]. 

Argentometric titration involves the titrimetric determination of an analyte using silver nitrate solution as titrant. Its application in environmental analysis is limited to the determination of chloride and cyanide in aqueous samples. The principle of the method is described below. 

Titrimetric measurements alkalinity titration for carbonate and bicarbonate ion determinations, argentometric and potentiometric titrations for determining chloride, and iodo-metric titration for sulfite, chlorine, and dissolved oxygen. 

Sulfate and chloride Ion were measured by ion chromatography using a Dionex model 20101 system on samples from Great Sippewissett Marsh. On samples from Great Marsh, sulfate ion was determined gravlmetrically as BaSOj and chloride ion was determined by an argentometric Mohr titration. 

Several methods can be used for the determination of chloride in water [2], The argentometric and mercuric nitrate methods are based on the titration of chlorine in the presence of an indicator. Experimental procedures are easy, but many substances may interfere with the results. There are also other methods such as potentiometry, capillary electrophoresis and other automated methods (ferricyanide method or flow injection analysis). 

The first comment that must be made is to assert that it is a prototropic back fixation with sulfuric acid, and not only an argentometric fittafion, although, in the procedure, a quantitative determination of chloride ions is mentioned. The fixation of chlorine ions with silver ions is used to be sure that an excessive consumption of hydroxide ions does not exist. In fact, it is just this excessive consumption of hydroxide ions that liberates the chloride ions from chloroform. In other words, the consumed hydroxide ions that correspond exactly to the concenXafion of chloral hydrate are those given in the first chemical equation. The second comment is that Mohr s method is particularly well adapted to determine the liberated chloride ions, due to the basic pH of the solution imposed by the use of phenolphthalein as indicator ... 

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