Acuyo
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Reaction byproducts of H2SO4 and NaCl?
If it's sodium sulfate, it's useful isn't it? Maybe for drying?
H2SO4 + NaCl -> HCL + H2O and maybe some sodium sulfate?
That's my best guess, any comments appreciated
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gluon47
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Your equation is impossible. To put it simply, Both sides of the equation must contain the same atoms in the same amounts. I suggest you learn more
about balancing equations.
The reaction produces hydrogen chloride and sodium bisulfate.
H2SO4 + NaCl ==> HCl + NaHSO4
Upon strong heating, some but not all of the sodium bisulfate may react with any excess sodium chloride to give sodium sulfate and more hydrogen
chloride.
NaHSO4 + NaCl ==> HCl + Na2SO4
98% sulfuric acid and sodium chloride are commonly used to generate hydrogen chloride gas for reactions.
[Edited on 10-2-2017 by gluon47]
reality is an illusion 
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Acuyo
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I know the mechanism is wonky, that's why I asked in beginnings, I've never taken a chem class and I'm well aware I need to learn -- thanks for
reminding me of that.
OK so, (dirty) Sodium Bisulfate ( it wasn't ever heated)
thx
[Edited on 10-2-2017 by Acuyo]
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alking
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Sodium sulfate is good for drying, but unless it's pure I wouldn't use it as such. Generally one would use Na2SO4 to dry things that are sensitive to
other drying agents, otherwise it's rarely a first choice. If it's contaminated with bisulfate it loses that usefulness as bisulfate is acidic. Pure
Na2SO4 is also incredibly cheap so I wouldn't even bother recycling it if it were pure, it's just not worth the time or energy expended unless
processing a large batch.
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chemplayer...
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On the equation, simplifying a little bit (forgetting ions), think of a salt as a combination of an acid and a base, e.g. NaCl (sodium chloride common
salt) is made from HCl (hydrochloric acid) and NaOH (sodium hydroxide). The equation when they react is:
Na-OH + H-Cl => Na-Cl + H-OH (which is water, H2O)
In the salt which forms you've always got a part which was derived from an acid (Cl) and a part derived from a base (Na).
By reacting NaCl with sulfuric acid you are effectively 'swapping' the acid round; in plain English, sulfuric acid + salt -> hydrochloric acid + a
new salt. The part which makes the acid 'acidic' is the hydrogen, so this is what is ultimately swapped. If 'XXX' is the part of the acid excluding
the hydrogen, then generally:
H-XXX + Na-Cl => Na-XXX + HCl
We're swapping the acid bits (hydrogen) round to make hydrochloric acid (or hydrogen chloride gas) and a new sodium salt.
Sulfuric acid looks a bit more complicated because it's got TWO hydrogen atoms in it. One of these hydrogens can be swapped easily. The other requires
a bit more effort (e.g. higher temperature). The formula of sulfuric acid is H2SO4 and when swapping the first hydrogen off, the remaining bit (the
'XXX') is called 'bisulfate' which is HSO4 (i.e. one H has gone).
So:
H-HSO4 + Na-Cl => Na-HSO4 + H-Cl
The product is sodium hydrogen sulfate, which is what you get when you add cold sulfuric acid to NaCl salt (as well as clouds of HCl gas). If you heat
the mixture then you can get another reaction happening. This is where the bisulfate also acts as an acid and you can swap out the remaining hydrogen:
H-NaSO4 + Na-Cl => Na2SO4 + H-Cl
Now the result is another swap where all the hydrogen atoms in the sulfuric acid are now replaced with sodium. The product Na2SO4 is sodium sulfate.
You can combine the above steps into one - because ultimately one sulfuric acid can react (with lots of heat) with two NaCl:
H2SO4 + 2NaCl => Na2SO4 + 2HCl
So a challenge. Just as you can sometimes 'swap' round acids in this way, you can also sometimes swap around bases. If we mix together sodium sulfate
(a salt) and calcium hydroxide (a base), what could the products be?
Na2SO4 + Ca(OH)2 => ???
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