Re: Re; dead battery

Allan Adler <ara@xxxxxxxxxxxxxxxxxxxx> writes:

To separate the MnO2 [snip]

Assuming I managed to separate out the MnO2, is it possible to use it to
grow a large single MnO2 crystal? For example, it is soluble in HCl, so maybe
one can grow it from solution. I've grown crystals from aqueous solution and
am not sure how one would proceed with HCl solution. With aqueous solution,
one lets water evaporate slowly, whereas I probably don't want HCl to just
evaporate. So, maybe the thing to do is put the HCl/MnO2 solution in a
beaker in something like a distillation apparatus, except that it isn't
heated. The sole purpose of the apparatus is to control where the HCl vapor
goes when it evaporates. The other thing is that, when I grow crystals from
aqueous solution, I hang a little seed crystal from a string in the solution.
I'd need to hang it from something that would not dissolve or react with the
HCl.

Well, ok, to grow crystals from aqueous solution, I first heat the water to
increase the solubility of the substance in the water, so that I get a
supersaturated solution when it cools. I'd have to heat the HCl to
imitate that, but that might not be a good idea because I don't have
a hood and, also, the msds for MnO2 says there is a hazard from heating it,
so maybe I also shouldn't add it to hot HCl. An alternative might be to
dissolve as much MnO2 as I can in HCl at room temperature and then keep
the solution at a much lower temperature in the distallation apparatus
and let the HCl slowly evaporate. Although slow evaporation is desirable
for good crystals, cold temperature evaporation might be too slow. But maybe
it can be accelerated by making the vessel for the "distilled" HCl much
colder.
--
Ignorantly,
Allan Adler <ara@xxxxxxxxxxxxxxxxxxxx>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.

Relevant Pages

  • Re: dead battery
    ... I took at face value the table in the CRC handbook ... be inaccurate for the CRC handbook to say that MnO2 is soluble in HCl ...
    (sci.chem)
  • Re: dead battery
    ... at "Laboratory experiments in general chemistry. ... Identify the gas that is evolved. ... be inaccurate for the CRC handbook to say that MnO2 is soluble in HCl ...
    (sci.chem)
  • Re: Manganese (IV) in concentrated HCl?
    ... from MnO2 or permanganate oxidation with conc. ... HCl. ...
    (sci.chem)
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