Complex Compounds of Tin

Alternatively weigh out accurately about 0.25 g of your product into a stoppered bottle and then add 30 cm of cone, hydrochloric acid and 3 cm of chloroform. 

Titrate with standard 0.025 M potassium iodate solution, vigorously shaking after each addition of the solution, until the violet colour of the organic phase is just discharged. The aqueous layer will be pale yellow in colour at the end-point. 

Sn(II) or Sn(IV) in the form of chloro-complexes can be precipitated with large cations e.g. /raM5-[Co(en)2Cl2r (Sec. 14.8.1). 

Weigh our 2.25 g tin(ll) chloride dihydrate, add enough ammonium chloride to dissolve the solid in water. Heat to the boiling point and add, slowly and with stirring, a concentrated solution of the cobalt(lII) complex until precipitation seems complete. Filter under suction and wash on the filter with ethanol and continue suction while pressing between filter paper. Weigh your product and calculate the % yield based on Sn. 

The complex can be analysed for chloride by dissolving in dilute nitric acid and titrating chloride with silver nitrate. 

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