Aurum - 23-9-2006 at 02:30
I just got some HCl acid today from the pool shop and noticed that they have "non fuming acid". I asked the shop keeper what it was and he said it was
a mineral acid substitute for hydrochloric. A quick google makes me suspect it's sulfuric acid. At US$6 for 5Ltrs it's pretty cheap.
Can anyone confirm/refute that it's sulfuric?
It states 30% by volume. Is this around 6 molar? (98% being 18 molar) The HCl is around 10 molar and so I would expect it to be around the same, so
I'm a little confused.
Thanks.
Edit, would I be right in thinking that H2SO4 would be twice as effective at changing PH compared to HCL due to the 2 hydrogens. If so, 5 molar would
make sense.
[Edited on 23-9-2006 by Aurum]
Pyrovus - 23-9-2006 at 03:18
It might be a solution of NaHSO4. They often use that as a pH reducer, although usually in the solid form.
Nerro - 23-9-2006 at 03:20
No because only the first H will come off in any realistic situation. HSO4- is not that acidic in an allready acidic solution.
And I thought that HCl was added to pools in conjunction with hypochlorite solutions so as to release Cl2 in the water. H2SO4 would not do that.
Can you describe the "acid" please?
not_important - 23-9-2006 at 05:45
No, acid is added with the intent of controlling pH. Sodium bisulfate and carbonate are often used to lower or raise the pH.
It's likely to be sulfuric, the label should tell.
Aurum - 23-9-2006 at 15:32
I'll go and buy some on Monday and try and figure out what it is. If it turns out to be useless I can still put it in the pool.
I've got some calcium nitrate, will this confirm that this is sulfuric based or would another acid also cause a precipitation?
Is there a simple way do tell which it is, sulfuric of sodium bisulfate. I could boil it down and see if I get crystals.
The label simply states "contains mineral acid".
In a swimming pool situation (neutral) would 5 molar H2SO4 = 10 Molar HCl as far as controlling PH goes?
Thanks.
not_important - 23-9-2006 at 22:01
Phosphoric would give a ppt of a calcium phosphate. The mineral acid suggests it is not bisulfate. Boiling down a few ml in a test tube would be
worthwhile, bisulfate will give a solid, sulfuric will get 'oily' and give off SO3 eventually and should leave little or no trace when taken to
dryness, H3PO4 will just get thick until around red heat.
Given that bisulfate - NaHSO4 - is also used for lowering pool pH, I suspect sulfuric will work as two moles of H+
evil_lurker - 23-9-2006 at 22:08
Wouldn't be phosphoric, that would cause algae growth...
not_important - 23-9-2006 at 22:17
Also cause solid Ca/Mg phosphates to build up on surfaces. And, yes, it's not used that I've read of, but the heat test is a simple confirmation.
Nerro - 24-9-2006 at 05:32
5M H2SO4 =/= 10M HCl because the conjugate base of sulfuric acid is not a strong acid. HSO4- simply will not completely dissociate.
not_important - 24-9-2006 at 06:09
Doesn't need to completely dissociate under concentrated condistions, it's not going to be very concentrated in its end use.
Bisulfate's Ka is on the order of 10-2, which is way more acid than pool water should be, both protons are going to pop of that sulfuric acid to give
sulfates if dumped in any real pool or spa. And there is no way any ordinary swimming pool is going to be even 0,1M in anything except water.
Aurum - 24-9-2006 at 06:16
Nerro,
Were talking about putting 2 Ltrs into 85,000 Ltrs to change the PH from 7.8 to 7.5, does this make a difference. The reason I ask is that this acid
is sold as equivalent to 10M HCl and has a concentration of 30% which if it is sulfuric would be around 5M.
Mike.
vulture - 25-9-2006 at 01:36
Given the application and the concentration we're talking about, HSO4- will certainly be adequate.
Aurum - 26-9-2006 at 00:55
I bought some today and tried a few things.
With Ca(NO<sub>3</sub>
<sub>2</sub> it causes a precipitate.
However, when I boiled it down and let it cool it formed needle like crystals so I'm guessing it's NaHSO4 solution. As I already have a couple of
kilos of NaHSO4 then it looks like the "Non fuming acid" is going in the pool.
stricnine - 11-10-2006 at 13:56
A few drops of Ag NO3 would clarify a bit the issue:
If there is Cl-, then AgCl should precipitate massively (white-curdy lookin')
If there is SO4=, you will see some ppt, but not so "massive". If you got some sulphate, prepare some solutions and compare it with some chloride ppt
(dissolve some tablesalt + add the silver nitrate and compare), and work out your decision. The same if there is phosphate.
Flame test of the liquid should stain the flame with a bright yellow colour if there is sodium present.
To test for chlorides: get a copper wire, clean it with some nitric acid, rinse it with distilled water and pass it over the flame, nothing impressive
would be seen, but if you wet the wire with a solution where Cl is present, the flame turns deep green (Beilstein test for chlorides!)
You can get silver nitrate from some little pencils that are meant to cure warts.
Enjoy!
Fluorite - 2-1-2021 at 06:21
https://www.jumia.com.tn/sans-marque-ph-pour-piscine-5-kg-16...
Is this sodium bisulfate? Please help
[Edited on 2-1-2021 by Fluorite]
unionised - 3-1-2021 at 04:12
Given that it says
"VENDU AVEC LE PRODUIT
5 kg de bisulfate de soude en poudre pour le traitement des eaux"
I'd assume it's sodium bisulphate.
macckone - 3-1-2021 at 23:25
One note, not the product that the OP was talking about.
There is also 'safer acid' which is 20% HCl.
It is below the azetropic mix.
It is sold as a less fuming mix.