Azane
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Chlorine production
So it's pretty well established that hydrogen chloride/hydrochloric acid can react with hypochlorite salts to form Cl2 and the salt's
corresponding hydroxide and/or chloride, depending on the stoichiometry.
LiOCl + HCl --> Cl2 + LiOH
or
LiOCl + 2HCl --> Cl2 + LiCl + H2O
However, I was wondering if it's possible to substitute the HCl with a metal chloride.
LiOCl + LiCl --> Cl2 + Li2O
in aqueous solution:
LiOCl + LiCl + H2O --> Cl2 + 2LiOH
I won't make any claims that the reaction using a metal chloride would be more favorable. Rather, I'm interested in using a metal chloride simply
because it can be handled more easily and safely than aqueous HCl.
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bismuthate
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That won't work. HCl is much more easily oxidized that LiCl, plus it wouldn't form the hydroxide in an acidic environment.
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Darkstar
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Your first equation is wrong. It should look like this:
LiOCl + HCl ⇌ HOCl + LiCl
Your second equation, however, is correct:
LiOCl + 2 HCl ⇌ Cl2 + LiCl + H2O (added equilibrium arrows)
Keep in mind that hypochlorite is essentially in a pH-dependent, three-way equilibrium with hypochlorous acid and elemental chlorine. I briefly
explained this in a previous thread.
Also, your third equation won't work. The reason Cl2 is produced when you add an acid, especially HCl (additional chloride ions), is
because protonation of the hypochlorite ion activates it for substitution by chloride. The acid initially protonates hypochlorite to give hypochlorous
acid. If the pH is low enough (this next step is partially speculation, as I'm not entirely sure the exact details of this mechanism is actually
known), hypochlorous acid may undergo a second protonation, forming a charged hypochloronium ion (H2OCl+). This ion is highly activated for
nucleophilic attack on its chlorine, and if a chloride ion ends up attacking, Cl2 and H2O are formed.
Thus the overall reaction of going from hypochlorite to elemental chlorine looks something like this:
ClO- + H+ ⇌ HClO
HClO + H+ ⇌ H2OCl+
H2OCl+ + Cl- ⇌ Cl2 + H2O
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