[daveyboy]

A while ago I learned about how to dilute the various concentrations of PH of substances to make them back to neutral and safe. I wrote a nice big document on it, then my hard drive died and so now I'm going to have to learn it all again quite quickly unless one would be so kind as to teach.

I have spilled some fairly heavily concentrated caustic soda on my floor. Bottle says "drain cleaner" level is 250g mixed with 8000 ml of water. I mixed 3g with 100 ml of water then dumped it on some gunk that I could not get to come off. Well, the gunk very nearly has loosened up enough to scrape off now but the problem is the water is evaporating and so i got bits of caustic soda lying around.

What dilution of citric acid should I dump on the spill area to make it safe?

[AWK]

CO₂ from air soon resolvea the problem

[daveyboy]

Thank you very much for your answer but now it leads to more question.

I have tried a LOT of approaches at removing this stuff. Caustic soda has been the most effective. Just how much can I dump on the floor and expect CO2 to fix, why does CO2 fix it and how long does that take (I expect if I knew why CO2 fix I could answer third question)

[daveyboy]

BTW I'm not just sitting here waiting for you to answer I'm googling my ass off trying to answer the question of diluting bases myself, I DID research this once before as I find caustic soda to be an amazing cleaner and I wrote it all out before losing in HD crash. If I manage to work it out I'll post the answer here.

Won't bother with the CO₂ fixing thing though that went way over my head.

[billnotgatez]

Would vinegar neutralize caustic soda?

[Grundalizer]

If you have enough sodium hydroxide on the ground, and it is somewhere you walk with bare feet or have kids or dogs walking, I would recommend neutralizing.  You could clean it many many times with water, to dilute it, but I don't know what floor it is on.

Is it on a wooden floor inside or something?  Outside on a concrete floor in the garage? 

If I am reading you correctly, the concentration solution is 250g NaOH into 8000mL (8L) of water, which is a 0.77M solution of Sodium hydroxide, not very concentrated, but could cause some chemical burns as its pH is 13.9 (14) for all intensive purposes.

Now I don't get what you mean by

I mixed 3g with 100 ml of water

  did you take 3g of the concentrated solution (3mL?) and put it in 100mL of water?  Or did you take 3g of NaOH and put it in 100mL of water?

Now, if you have 250g NaOH per 8L, then you have 30.8g NaOH per 1L, and 3.08g per 100mL, or 0.031g per 1 mL so if you took 3mL of the concentrated solution (about 3 grams) and put it into 100mL, you would only have about 0.093 ( about 1/10th of a gram) of sodium hydroxide in the solution.  For that, I would say don't even bother neutralizing it, just dump some water on it and try and soak it up.

Either way, it looks like you are dealing with small amounts of NaOH and water dilution is your best bet.  If it is where children or pets walk, then sure maybe a little vinegar or citric acid diluted in water might help, but it would also smell for a while.

[daveyboy]

Thank you!