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       #Post#: 47--------------------------------------------------
       NEUTRALIZING A PLATINIC ACID SOLUTION
   DIR By: Dr. Poe
       Date: November 5, 2013, 3:56 am
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       Hexachloroplatinic acid, ( H2PtCl6·6H2O: ) also called
       Chloroplatinic Acid,  complex compound formed by dissolving
       platinum metal in aqua regia (a mixture of nitric and
       hydrochloric acids) or in hydrochloric acid that contains
       chlorine where it is very slightly soluble. It is the starting
       material from which most platinum compounds are made and
       crystallizes from the solution as reddish brown deliquescent
       (moisture-absorbing) crystals with specific gravity 2.43 and
       melting point 60° C .  When one adds an alkali or an alkali
       carbonate to this solution the pH rises at first then reverses
       direction and the solution becomes more acidic. This is because
       a new, different acid is formed as the chlorine is replaced by
       'OH" groups.  The new acid formed is stronger than
       hexachloroplatinic acid having a formula of H4PtCl2O2 or
       H4Pt(ClO)2.  The continued addition of the alkali lowers the pH
       into the negative region and then with again continued addition
       of more alkali the pH again reverses direction and starts to
       rise rapidly with the formation of the weaker acid H2Pt(OH)6.
       This acid will precipitate as a white crystal when the pH
       reaches 7 pH.  insoluble in water---Dr. Poe Geochemist Rex :o
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