Sodium hexanitrocobaltate

When a test confirms the presence of a substance without determining the amount of substance present, the process is called qualitative analysis. In this activity, you will detect the presence of potassium in coffee by the characteristic yellow color that appears when potassium ions react with sodium hexanitrocobaltate. To make it easier to detect the yellow color, the coffee solution will be decolorized with charcoal, an allotropic form of solid carbon. 

Sodium hexanitrocobaltate is an irritant, slightly toxic, and a possible sensitizer. 

To each of the three labeled test tubes, add 5 or 6 drops of nitric acid and 1 mL of sodium hexanitrocobaltate. Record the color of these solutions in Data Table 1. 

Sodium hexanitrocobaltate (III) Hexamminecobalt(III) chloride Carbonatotetramminecobalt(III) nitrate... 

Twenty grams of sodium hexanitrocobaltate (III) (No. 7S) are dissolved in 200ml of water and 15g of potassium acetate in 100ml of water are added. The light-yellow potassium salt that precipitates immediately is washed on the filter with alcohol and acetone. 

Sodium hexanitrocobaltate (III) (Na3[Co(N02)6]) Tartaric acid solution (sodium acetate buffered) Yellow precipitate of potassium hexanitrocobaltate (III) insoluble in acetic acid White precipitate of potassium hydrogen tartrate... 

Seven grams (0.017 mol) of sodium hexanitrocobaltate-(III) is dissolved in 15 ml. of water, the solution is heated to 50°, and 2.7 ml. of diethylenetriamine is added. A yellow crystalline precipitate forms, which grows as the solution is cooled. The precipitate is filtered with suction and washed several times with water and then with ethanol. A second crop of crystals can be obtained by concentrating the mother liquor. The yield is 3 g. (59%). 

Write the formulas for the following compounds (a) pentaamminechlorocobalt(III) chloride, (b) dichlorobis(ethylenediamine)platinum(IV) nitrate, (c) sodium hexanitrocobaltate(III). 

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