Neutralizing Muriatic Acid safely

Ocelaris · Mar 31, 2020

So I have been using Muriatic acid instead of vinegar lately, being very safe and all; but I always neutralize it before sending it down my 50 year old plumbing system. But I ran out of my go to neutralizer Sodium BiCarbonate and had some Kalkwasser lying around. Thinking I was spiff for using something I wasn't going to use any time soon, I tried it and got zero reaction... I know bleach + muriatic acid can produce dangerous vapors, but I figured kalkwasser being CAOH would produce CO2? I'm stumped that I didn't get anything, or maybe I didn't put as much acid in as I thought?

Can someone point me in the direction of safe/unsafe neutralizing bases for muriatic acid? Preferably products that we'll all have lying around anyways, i.e. sodium carbonate/bicarbonate kalkwasser etc...? Thanks!

Phildago · Mar 31, 2020

NaOH aka lye
The only products are water and NaCl

rmurken · Mar 31, 2020

Ocelaris said:
So I have been using Muriatic acid instead of vinegar lately, being very safe and all; but I always neutralize it before sending it down my 50 year old plumbing system. But I ran out of my go to neutralizer Sodium BiCarbonate and had some Kalkwasser lying around. Thinking I was spiff for using something I wasn't going to use any time soon, I tried it and got zero reaction... I know bleach + muriatic acid can produce dangerous vapors, but I figured kalkwasser being CAOH would produce CO2? I'm stumped that I didn't get anything, or maybe I didn't put as much acid in as I thought?

Can someone point me in the direction of safe/unsafe neutralizing bases for muriatic acid? Preferably products that we'll all have lying around anyways, i.e. sodium carbonate/bicarbonate kalkwasser etc...? Thanks!

Kalk will neutralize HCl. You’re not going to get bubbles though because there’s no CO2 to liberate. The reaction results in calcium chloride and water, and should generate quite a bit of heat.

I’d be careful mixing the two—both for the potential violence of HCl’s reaction with water, and the heat.

rmurken · Mar 31, 2020

Also reasonably dilute muriatic acid is great for cleaning stuff—much quicker than vinegar. I have also heard some say the acetate in vinegar can weaken certain types of plastic, making a mineral acid a better choice.

Randy Holmes-Farley · Apr 1, 2020

As mentioned, dilute it and then mix with calcium hydroxide (if that is what you are using) until no more dissolves. When solids remain, it is nuetralized.