Prep. Directions,for making this solution are given under Platinum, page 111.

Use. This solution is used for testing the presence and absence of potash, in various substances; it forms with potash a double chloride, K Cl, Pt Cl2, very sparingly soluble in water, insoluble in ether and alcohol; with soda, on the other hand, no precipitate is formed, and hence it is used to distinguish between the potash and soda compounds. With this view it is applied to test potash, sulphate of potash, bicarbonate and carbonate of potash, the chlorate, the citrate, the permanganate and the acid tartrate of potash, the bicarbonate and carbonate of soda, chloride of sodium, and liquor sodas chloratae.

The solution of bichloride of platinum is also used as a test for the presence of nicotine in the distillate obtained by distilling tobacco leaves with solution of potash. It forms with that substance a yellow crystalline precipitate, a double chloride of platinum and nicotine.