Thread: Hydrochloric Acid on Concrete

I really was under the impression that H2 was released.

It is. The first reaction we talked about would be happening too. (I think.)

But I guess that half the H2 it generates would react with the second reaction's O2 to create H2O, so more CO2 is realeased to air than H2

Did I mention that I'm really glad I don't do this for a living? I'd be sacked only a couple of hours into the job.

Yeah, from memory this would have been first year high school chemistry!

Now that I think on it, I vaguely recall an attempt at anenvironment in a sealed dome (an experiment in closed system ecologies) that failed because significant amounts of O2 were disappearing and they couldn't balance the eco-system. Apparently 'twas all due to the foundation cement curing and releasing CO2.

Or something like that...

Thanks Guys,
I was expecting a fairly simple answer, I suspected chlorine gas might have been in it.
I think I'll restrict myself to saying that a highly toxic gas is given off and not get any more detailed.

Cheers
Bill

Originally Posted by Skew ChiDAMN!!

... gimme a handful of nitropills and a bucket of dieseline any time!

Nah!

Open bucket of Pool Chlorine and a leaky container of Brake Fluid
Now at opposite ends of the shed

YES!!!
There is still Fly Ash in concrete

As a geologist myself, I'd be willing to bet most gas given off would be CO2. Colourless and odourless.

You'd smell it if any chlorine gas was given off - given my uni-level chem is getting a tad old, I'd say the chlorine would prefer to bind up as CACl2 (common kettle-scale), as its easier to form the CaCL2 ionic bond over the higher energy Cl2 gas covalent bond. Which leaves the H to bind with any free CO3 carbonate in the concrete, which'd produce water and CO2.

Many of the rocks where I work (a lead mine) are very lime-rich and fizz rather vigorously when acid is applied! We have a funky test where we let the acid sit for 30 seconds or so, then spray the rock with potassium iodide (KI). Lead in the rock freed up by the acid grabs the iodine and goes brilliant yellow (the old yellow paint dye colour). Can be very strong sometimes where the rock is up to 40% lead by weight!

Cool.

http://www.ceramics-silikaty.cz/2000...000_03_114.pdf

After reading this I don't feel much wiser...

It's not Hydrogen.. thats HCl and metal

reactions with hydroxide should leave a salt and water...

CO2 is probably most likely

Pulse