0

To shock a swimming pool one uses either calcium hypochlorite ($\ce{Ca(ClO)2}$), commonly sold from at least one major brand in pouches,

hth Super

or the more obscure "liquid chlorine".

liquid chlorine

I'm saying "obscure" because labels for liquid chlorine never list the compound.

But unlike the result of dissolving $\ce{Ca(ClO)2}$ in water, which results in, by definition, a bleached (white) color, liquid chlorine is, somewhat surprisingly, yellow.

Are liquid chlorine and super-shock chlorine the same?

Mithoron
  • 4,546
  • 14
  • 40
  • 61
Sam7919
  • 153
  • 3
  • 1
    Note that mentioned "liquid chlorine" is far from true liquid chlorine, which boils at -34°C and was used in WWI at Somma in 1915 as chemical weapon – Poutnik Jun 18 '22 at 22:57
  • @Poutnik Interesting (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2376985/). In 1915 a gas attack was as obscure to French soldiers as a nuclear explosion was to the Japanese in 1945, and in both cases no amount of running could save the soul of those attacked (though a bicycle or an automobile could arguably save the life of someone in the former, but perhaps not in the latter case). – Sam7919 Jun 20 '22 at 14:41
  • @Poutnik In any case, back to the present day. The major powers have neutralized the temptation of the rogue leader of another army to use these weapons by maintaining themselves a cache. That is small consolation for the Ukrainians who have abandonned, willingly, WMDs. – Sam7919 Jun 20 '22 at 14:42
  • @Poutnik I still digress. The important point in the present context is to highlight why chlorine gas is not sold for swimming pool maintenance. It might be highly effective. A small container would last a month (?) and could be adjusted at will to raise/lower the concentration depending on whether swimmers are expected. But the risk of misuse of chlorine gas trumps any potential benefit for civiilan use. I wonder whether this is about right. – Sam7919 Jun 20 '22 at 14:45
  • 1
    Manipulation with elementary chlorine is not convenient and is potentially very dangerous, in case the gas escapes. Chemically bound chlorine, that is created in water in situ at reasonable concentration is much, much better way. – Poutnik Jun 20 '22 at 14:48

1 Answers1

2

Liquid chlorine is probably bleach, which is a solution of sodium hypochlorite $\ce{NaOCl}$. This substance is obtained by dissolving chlorine $\ce{Cl2}$ in a solution of sodium hydroxide $\ce{NaOH}$, according to $$\ce{Cl2 + 2 NaOH -> NaOCl + NaCl + H2O}$$ Chlorine is produced by adding an acid to this solution : the acid destroys $\ce{NaOH}$ and produced free chlorine $\ce{Cl2}$ by reversing the previous equation (which should be written as an equilibrium). Even weak acids like carbonic acid (and $\ce{CO2}$) can do the job. This is why the solution deserves to be called "liquid chlorine".

Maurice
  • 28,241
  • 3
  • 29
  • 61