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       #Post#: 132--------------------------------------------------
       Sulfur dioxide
   DIR By: Michel
       Date: May 11, 2012, 8:27 am
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       When powdered sulfur is heated with a strong oxidizing agent
       like lead dioxide, the sulfur melts at it's melting
       point(113'C), continued heating decomposes the lead dioxide at
       its decomposition temperature
       PbO2--->Pb+O2
       Sulfur then burns immediately in the oxygen produced. If they
       are mixed in stoichiometric amounts, Sulfur dioxide is produced.
       This sulfur dioxide can be dissolved in NaOH to produce Sodium
       Thiosulfate. Sulfur dioxide reaction with oxygen is not
       spontaneous at room temperature, so Sulfur trioxide cannot be
       prepared in large amounts at stp by mixing SO2 with air.
       However, SO2 does combine with NO2 to produce SO3 and NO.
       This reaction was very useful in the past when sulfuric acid was
       produced by the lead chamber process.
       Basically, the reactions involved
       i) 3S+2KNO3--->K2S +2SO2+2NO
       ii)S+O2--->SO2
       iii)NO+O2--->NO2
       iv)SO2+NO2--->SO3+NO
       The final step is the dissolving of SO3 in water at the bottom
       of the chamber to produce H2SO4
       This process can be done on a smaller scale since the reagents
       involved are cheap. See the link in this thread:
  HTML http://kolathechemist.createaforum.com/laboratory-chemistry/make-your-h2so4-yourself/
       #Post#: 710--------------------------------------------------
       Re: Sulfur dioxide
   DIR By: Shiva
       Date: September 24, 2012, 5:46 am
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       Nope, in industries, sulfur trioxide is dissolved in
       concentrated sulfuric acid to form oleum and adding it to the
       water to get the desired strength of sulfuric acid rather than
       mixing it with water as sulfur trioxide produces mist of
       sulfuric acid with water. Also, I never encouraged anyone to
       prepare sulfur trioxide as it is extremely dangerous. You should
       have fume hood in your lab to handle it. Still, it is very
       dangerous. I'm sure you do not want to char your lungs :-) It is
       one of the very dangerous compounds you could work with.
       #Post#: 711--------------------------------------------------
       Re: Sulfur dioxide
   DIR By: Michel
       Date: September 24, 2012, 5:59 am
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       --- Quote from: Shiva link ---
       >
       > Nope, in industries, sulfur trioxide is dissolved in
       concentrated sulfuric acid to form oleum and adding it to the
       water to get the desired strength of sulfuric acid rather than
       mixing it with water as sulfur trioxide produces mist of
       sulfuric acid with water.
       >
       --- End Quote ---
       This is true, but in the past, when Pb was about the only
       feasible material that wouldn't be attacked by conc. H2SO4,
       sulfuric acid was produced commercially by the lead chamber
       process with the reactions I described in my earlier post
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