If there are examples of quite pure metals that are similar in appearance (for example, palladium, platinum, silver), it can be relatively easy to distinguish them from each other, to determine the density of each sample.Since the density of pure silver, about 10.5 grams / cubic centimeter, palladium - about 12 grams (more precisely, 12.02) and platinum - about 21.4 grams.But, of course, such a method is permissible only for highly pure chemicals, in which the content of impurities is relatively small.
Accurately distinguish palladium from platinum can be the same, trying to dissolve a piece of material in the hot nitric acid. dissolved palladium, platinum - no.It diss
olves only in the famous "aqua regia" (a mixture of hydrochloric and nitric acid), and when heated.The cold "aqua regia" response is very slow.
geologists and chemists, analysts widely used qualitative determination of noble metals on the touchstone.It represents a specially made plate of a certain type of silicon oil shale.This touchstone has the following properties: it is very hard, inert to the corrosive substances (including strong acids and mixtures thereof), it has a fine-grained structure.
Qualitative analysis (sample) on this rock do this: take the test metal (or its alloy) and is carried out with a fairly tangible pressure on the wafer surface.Next should be clearly distinguishable, have a length of about 2 centimeters.Then act on the track specially prepared reagent and watch what will be the result.
If drawn feature left or palladium alloy, when exposed to a reagent consisting of a mixture of "aqua regia" and 10% potassium iodide solution quickly appears brighter, well distinguishable red-brownishspeck.This is because in the course of a chemical reaction, a substance K2PdCl4 - potassium tetrachloropalladate.