The Colors Black, Red, and Gold

Three 1-L beakers, six 150-inL beakers, iliree SO-ml. beakers, safety glasses, protective gloves. 

Potassium iodate, sodium sulfite, starch, concentrated sulfuric acid, glacial acid, sodium arsenite, sodium thiosulfate. The indicator solution II and the solutions A and B from the previous experiment are also required. 

200 inL ol water are placed in one ol llie large beakers, followed by 20 mL of a 1 % starch solution. 100 mL of a solution of sodium sulfite in sulfuric acid (made by adding 1.6 g Na2SOj (anhydrous) to a mixture of 1 L water, 10 inL ethanol and 4 g concentrated H2SO4) arc added with stirring, and finally the 

200 mL of the solution A are placed in the second large beaker 25 drops of the indicator solution II (see previous Experiment 28) arc added, followed by slow addition of 200 mL of solution B. The mixture is stirred for a few seconds, and after about a minute the red color is formed. 

200 mL of water are now added to the third large beaker, followed by 30 mL of glacial aceiic acid. Soliiiioiis of sodium arseniie (10%) and sodium thiosulfate (saturated, 100 mL in each case) are now poured in. The mixture is stirred for a short time and turns golden yellow after about 45 seconds. 

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