Volumetric analysis using silver nitrate

The preceding single or double distillation eliminates virtually all interfering factors. 

Glass beakers, magnetic stirrer with magnetic bar Burette, 10 ml, or flask burette Silver nitrate solution, 0.001 m  

The solution must be prepared freshly from 0.01 m silver nitrate solution each time it is used and its content checked. 

Dissolve 20 mg p-dimethylaminobenzylidene-rhodamine, Ci2Hl2 20 2 analytically pure acetone. The solution can be kept in a dark bottle for at least 1 week. 

The blank value is measured first, since the colour tone obtained is later used as a guide for the sample solution containing cyanide at the end of the titration process. Put 10 ml of 1 m sodium hydroxide solution into a glass beaker, add 20 ml distilled water and 0.1 ml indicator solution, then set the magnetic stirrer in motion. Immerse the tip of the burette in the distilled water solution and release enough silver nitrate solution to cause a change in colour from yellow to yellow-red or salmon-pink. The colouring only remains for a short time. 

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Dissolve 25 mg analytically pure potassium cyanide in 1 litre of 0. m sodium hydroxide. 1 ml of this solution contains approx. 0.01 mg cyanide ions and its factor is determined by titration with 0.001 m silver nitrate solution (see "Volumetric Analysis using Silver Nitrate"). 

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