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AJKOER
Radically Dubious
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Just came across the following reported reaction at http://sulphur.atomistry.com/hydrogen_sulphide.html :
S + 3Cl2 + 4H2O = H2SO4 + 6HCl
which is really a confirmation of the hypochlorous acid approach.
I am reporting it as it also suggests a simply process to prepare H2SO4. Just make a suspension of sulfur in water. Pour it into a large vessel filled
with chlorine. Shake and let stand. Pour out the treated chlorine water with sulfur, and refill the vessel with chlorine. Add back the previously
treated chlorine water with sulfur and shake. Keep repeating the process until the sulfur has vanished.
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A few paths to chlorine, like adding NaHSO4 to chlorine bleach (NaOCl).
A more accessible path, but not returning the same proportion of Cl2, start by adding lemon juice, or Ascorbic acid (Vitamin C) to a source of NaOCl,
a piece of copper (perhaps a coin, or substitute a piece of carbon), some Aluminum foil (best if preheated in a flame) and finally a large excess of
NaCl. The electrochemical reaction results in chlorine. Reference: see https://www.sciencemadness.org/whisper/viewthread.php?tid=33...
[Edited on 10-12-2019 by AJKOER]
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woelen
Super Administrator
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NaOCl added to bleach indeed works quite well. Gives gaseous Cl2 and Na2SO4, which will separate in large crystals as its 10-hydrate.
The other path to Cl2 is totally useless. Adding all those reductors to NaOCl, do you really think that produces Cl2 in significant amounts? Not at
all. Ascorbic acid is too weakly acidic and too strongly reducing to give any decent production of Cl2 with NaOCl. There certainly will be a reaction,
but not what is needed.
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Whether the making of H2SO4 from S, Cl2 and water works in practice should be tried. The reaction in theory can occur, and I also think that in
practice it can work. If S is oxidized by Cl2 in the presence of excess of Cl2 and water, then indeed you get H2SO4 and HCl. But from an engineering
point of view, I expect this method to be very cumbersome and slow. Cl2 does not dissolve that well in water, powdered S is somewhat hydrophobic and
is not easily wetted and it will be hard to get it nicely suspended in water. I think that for making a few ml of H2SO4, you'll need a LOT of time and
frequent adding little amounts of Cl2 to the reaction mixture.
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AJKOER
Radically Dubious
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From an old thread, which also provides this statement per a cited source:
"3 HOCl + Al --> Al(OH)3 (s) + 3/2 Cl2 (g) Eo net = 3.93 V
This battery cell is theoretically capable of generating 3.93 volts.
Reference: see http://www.exo.net/~pauld/saltwater/ "
Quote: Originally posted by AJKOER  | I agree that this is not a classic quick (forceful) chlorine generation tool. It may, however, be a gradual long lasting method for some
applications. Note, there is quickly an evident chlorine smell, so perform this experiment in a sealed chamber or outdoors.
Some Chlorine probably reacts with water as follows:
Cl2 + H2O <-----> HCl + HOCl
, which is not completely a bad thing as more hypochlorous acid will fuel the battery and eventually form more Cl2 and Al(OH)3. ...
Heating the solution should help drive off any unreacted chlorine.
Bottomline, not a great path to rapid, or possibly abundant chlorine generation (due to secondary reactions), but does have interesting side
products.
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[EDIT] I repeated the experiment, using an old pre-1982 penny, which is brass, 95% copper, 5% zinc (please see
http://en.wikipedia.org/wiki/Penny_(United_States_coin) ) and added no NaCl to the solution this time (the Cu/Zn alloy is apparently more reactive
than pure Cu). I also moved the copper anode to be near the top of the battery cell.
Now, Chlorine is formed at the copper cathode with hopefully reduced solution contact by the reaction :
3 HOCl + 3 H3O+ + 3 e- ⇒ 3/2 Cl2(g) + 3 H2O
and today I noticed more solids suspended in the solute with a tint of green. I suspect the formation of some copper hydroxychloride, Cu(OH)2.CuCl,
which exists as a greenish insoluble solid in near neutral solutions (see http://en.wikipedia.org/wiki/Copper_oxychloride ). I also observed possibly more Chlorine generation as there was as an obvious gas buildup. Now,
this is most likely not entirely H2 given the rapidity of its creation and the avoidance of employing any excess Aluminum (the Al was completely
dissolved in the first few hours).
I wish to thank Cou for his comment as the source of the inspiration to move the copper cathode to a higher position in the battery cell. It appears
to have increased Cl2 output and created a more visible alternate oxychloride.
............................
[Edited on 5-9-2013 by AJKOER] |
And this reported result by Plutonium239:
| Quote: Originally posted by Plutonium239 | | I just did this last night. So much chlorine was produced that the stopper on my flask was blown off, but it all turned out well. Now I have a
really cool sample of chlorine. |
So, some mixed results (fine-tuning required, like does excess Cl- salt out the Cl2, or consumes it via Cl2 + Cl- = Cl3-). However, some potential
with the last comment above being an example of one of the stronger reaction results reported. I suspect the recommendation to place the copper
cathode near the top of the solution, as Cl2 is generated at the Cu electrode, may avoid/limit chlorine loss. This is an important point for potential
harvesting of Cl2 from HOCl (formed from a weak acid acting on NaOCl) via an electrochemical (battery) cell design without the need for employing a
strong acid.
Note, electrochemical reactions characteristically display an inception period, during which there is no obvious reaction. However, in general, I have
noticed that, at times, a short microwaving can eliminate/shorten an inception periods. However, in the current experiment, a rapid generation of
chlorine while undergoing a short MW treatment, could be problematic and require safety measures. If successful, however, resulting in either timely
significant ongoing Cl2 generation or very rapid production, that would be quite interesting.
[Edited on 10-12-2019 by AJKOER]
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