Alternative procedures for anions

Alternative procedures for a few anions are summarised here. Section references are to the gravimetric procedure already given for the particular anion. 

Prepare the reagent by shaking vigorously 4.0 g of triphenyltin chloride with 200 mL of 95 per cent ethanol. Filter any undissolved residue and dilute with an equal volume of 95 per cent ethanol. 

Perchlorate as potassium perchlorate (ca 400 mg as the sodium salt in 25 mL solution). Warm the solution to 80-90 °C and treat with a slight excess of a cold saturated solution of potassium acetate. Allow to cool and after 1 hour collect the precipitate on a weighed porcelain filtering crucible. Wash twice with 0.05M potassium chloride and then with four 5 mL portions of equal volumes of anhydrous ethyl acetate and anhydrous butan-l-ol. Dry the precipitate at 110°C for 30-60 minutes and then heat at 350 °C in an electric furnace for 15 minutes. Weigh as KC104 (Section 11.68). 

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