HCl 99% ?

[cheeseboy]

What's the highest % of HCl possible and why?
Don't Bee Careless, Bee Carefull & May The Source Bee With You...Always..

[Moriarty]

I could be wrong cheese, but I believe around %36 because it's just too saturated.  HCl is a gas that is Cl- and H3O+ when dissolved in water.  If one were to shoot for higher concentrations it would simply evaporate until it reached that stable equilibrium again.  You can buy the gas though.
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[Elementary]

1 kg of water saturated with hydrogen chloride at 15°c forms 1.75 kg of 43% solution, density 1.231.

By saturating a strongly cooled solution with the gas (HCl) three solid hydrates are formed : HCl,H2O (mp -15.35°c), HCl,2H2O (mp -17.7°c) and HCl,3H2O (mp -24.4°c).
(Rupert, J.A.C.S.,1909,31,851)
Umm, how interesting !!