Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Anonymous asked in Science & MathematicsChemistry · 1 decade ago

Can hydrofluoric acid (HF) dissolves gold?

2 Answers

  • 1 decade ago
    Favorite 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

  • panzo
    Lv 4
    4 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.

Still have questions? Get your answers by asking now.