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Can hydrofluoric acid (HF) dissolves gold?
- GeorgeSiO2Lv 71 decade agoFavorite Answer
Go to reduction potentials:
+ e− ⇋ Au(s) E° (V) = +1.83
H^+ + 2 e− ⇋ H2(g) 0.0000
To force the Au^+ rexn to an oxdn requires -1.83 V which since it is -ve is highly disallowed thremodynamically the rxn Au + 2H^+ ⇋ [Au^+-] + H2(g) goes not occur RTLnKeq = nFE°
You also cannot oxidize 2F^- to F2; F2(g) + 2 e− ⇋ 2 F− E° +2.87 V F2 just about is the least oxidizable substance known conc HNO3 acid is able to oxidixze Au to Au(III) giving reduced products of NO2. The Cl^ from cnc HCl can bind with Au^3= to give the soluble cmplx ion [AuCl4]^- which is soluble and allows attack of more of the Au surface bt HNO#. A 3:1 HCl:HNO3 (conc acides) is able solubilize Au (google aqua regia) So you can add conc HF to a mixture of Au and sand SiO2
SiO2 + 6HF → H2[SiF6] + 4H2O
Must use Teflon or polypropylene containers for rxn. And HF has a unique way of burning: it passes through the skin with very little pain and then starts eating your bone (F^- ion) which gives excruciating pain and is hard to treat: subcutaneous injections of calcium gloconate
- panzoLv 44 years ago
Acids can dissolve a physique greater thoroughly than lye—liquefying even the bones and tooth—regardless of the undeniable fact that it takes longer and could be dangerous. British assassin John George Haigh used sulfuric acid to dissolve a minimum of six of his sufferers interior the Forties. He processed the our bodies in a 40 5-gallon oil drum and suggested that the sufferers dissolved thoroughly in approximately 2 days. Do a calculation.