I’m asking this question for a friend (yes, really) so I’m a bit hazy on the concentrations involved but basically
There was a gallon of water to which was added 800cc of sodium hypochlorite and 200cc of hydrochloric acid. Some chlorine gas was released but what is the remaining solution? If it’s dangerous, is there a way to neutralize it? Just so no one thinks this guy was trying to make some sort of new drug what he was attempting to do what chlorinate latex. Thanks
It’s impossible to say without knowing the solution strengths of the various components. In general the two chemicals will mix to form sodium choride, free chlorine gas and water. But unless there were exactly enough of each to react completely with no leftovers, there will be some of one left.
What’s confusing him is that if he waits a day and stirs the mixture again he smells chlorine again. Is some of the chlorine staying in the water in some form?
If the hypochlorite solution was just the 5% stuff used in household bleach, you should be safe enough running it down the sink with plenty of water. The bleach breaks down at a rate which depends on the pH of the solution, so if he didn’t add enough acid, the process could take days. You’re better off disposing by dilution, than making an icky mixture worse by adding more acid.
Yup. And what’s left here is acid. Chlorine exists in water in three different forms depending on pH. Above pH 7.5, the major species is hypochlorite ion, (-OCl). Below pH 7.5 the major species is hypochlorous acid (HOCl) until the pH gets down a bit below pH 1 and then it exists as chlorine gas (Cl[sub]2[/sub]) which evolved, according to KidCharlemagne. So we know the pH is low.
[nitpick]The sodium and chloride ions remain as ions in solution. Evaporate the water and they’ll crystalize, becoming sodium chloride.[/nitpick]
And that’s about it. An acidic solution of sodium and chloride with some species of aqueous chlorine. We can spend time coming up with assumptions about the relative strengths of the different components and zero in on a likely pH, but if it was me, I’d be content pouring it down the drain and leaving the faucet running for a while. After all, it’s now ~25x weaker than the original 200ml of acid that was initially poured in.
Thanks for your help. I’ve already given him a good thrashing for his irresponsibility.
Add some Sodium Carbonate (Soda Ash - u can get it cheap from pool stores) and mix it - and watch the pH till you get neutral. That will take care of the Chlorine smell.