# Help identify acid



## lanfear (Jun 11, 2015)

Hi guys

I just want to clear this with you guys to be safe. I work at a garbage disposal station. We handle the garbage for 1 county, and people bring in their household garbage and have to sort it by type of garbage. So ocationaly there comes a can of acid. And when a gallon of HCl costs 56,3 $ you can understand why I want some free acid.
So this acid is just marked "acid" with a permanent marker. It is white fuming, and tests at 0 PH.
It will not dissolve copper nor silver. With a dash of H2O2 it turns green when i have a piece of copper in it. 
Can this be anything other than HCl? Should I do more tests before making my conclusion?

Jon


----------



## solar_plasma (Jun 11, 2015)

In my eyes this is just too dangerous, it could be a blend of just everything. 

If you know, it can only be a pure common acid (well, you don't!), then you could test for chloride by a AgNO3 test. This could be useful, if it is your own acid, you know, which acids you have and only the label has fallen off or unreadible.

In your case: Don't!


----------



## lanfear (Jun 11, 2015)

That is my feeling too, and that's why I posted this. To see if there was any possibility that this could be classified safe :| 
I do have to add one thing to my thought process. I live in Norway, and acid's are not easy to buy. The only acid that's available in stores are HCl. I have a business license but I could not get HNO3. You can't even get H2SO4. And these acid's came from consumers, so it is a good bet it is HCl.

Jon


----------



## solar_plasma (Jun 11, 2015)

I have no practical, handy and cheap idea. I hope someone else can help.


----------



## jason_recliner (Jun 11, 2015)

If it won't dissolve copper, but will dissolve tin, lead or solder, then you have further evidence of it being "consistent with HCl".
Then, if you get that far, and I don't want to suggest for a second actually _sniffing_ it, but HCl also has a quite distinctive aroma.


----------



## Geo (Jun 12, 2015)

Open a bottle of ammonium hydroxide (household ammonia) and your suspect acid and hold the containers close together. If it is HCl, a white smoke of ammonium chloride will appear in the air over the two bottles. Come on guys, all of you are better than me. You all are just holding back.

Edited for posting while asleep.


----------



## solar_plasma (Jun 12, 2015)

I think it is not the problem to find out, if there is HCl in this vessel. It is more, that you just can't be sure what else might be in it. Yes, probably it is just HCl, but I do not dare to advise anyone to use it. You can't be sure.

Another example: You find a canister of gasoline within some other garbage. You know it by its smell. Would you dare to put it into the tank of your these days common high tech car?


----------



## Geo (Jun 12, 2015)

Good point. Here in the US, we have a saying that may or may not be appropriate for this. If it looks like a duck and quacks like a duck, it must be a duck.


----------



## jason_recliner (Jun 12, 2015)

solar_plasma said:


> I think it is not the problem to find out, if there is HCl in this vessel. It is more, that you just can't be sure what else might be in it. Yes, probably it is just HCl, but I do not dare to advise anyone to use it. You can't be sure.
> 
> Another example: You find a canister of gasoline within some other garbage. You know it by its smell. Would you dare to put it into the tank of your these days common high tech car?


I may not put it in an Aston Martin. But I'd happily mix it with oil and feed it to the lawnmower.
Likewise, acid that quacks like HCl may not be selected for the second refine, but it's probably good for chewing up tin and lead.
Waste not, want not.


----------



## kurtak (Jun 12, 2015)

There are two common acids sold at hardware stores for household use (which could then end up going to the dump)

HCl - which is used to clean concrete, adjust PH in swim pools etc.

Sulfuric - used for drain cleaner

Finding nitric at a retail store is near impossible

A drop of sulfuric will result in a sputtering effect & HCl wont sputter - a drop of sulfuric on paper towel will eat the paper HCl wont

There is a concrete etchant made with phosphoric acid (with a bit of nitric in it I believe) but its uncommon to find it (home depot is the only place I have seen it) not sure how to test for it (it comes in a clear plastic jug - where as HCl & sulfuric come in white plastic jugs)

It would be very rare to see any other acids come to the dump from everyday household consumers 

Kurt


----------



## lanfear (Jun 12, 2015)

Yes that is my though also. The acid did not eat the PH paper so it's not Sulfuric. 
It forms ammonium chloride when I hold the bottles close. So I guess this will be my dirty work acid. Thanks to everyone for your help and inputs. I will not mix this acid with any other compounds, just to be on the safe side.

Jon


----------



## jason_recliner (Jun 12, 2015)

Here's a thought. If you added sodium hydroxide to a sample, and nothing precipitates but salt, is it a good indication that it at least contains no metals? Further evidence of it being consistent with clean HCl?


----------



## lanfear (Jun 12, 2015)

That is a good idea to. I will do that to be certain there is no metal contamination in it.


----------



## Lou (Jun 12, 2015)

Isn't muriatic 6 bucks a gal at the hardware store as concrete etch? It's the azeotropic 20% ish stuff but that's fine for refining.
In bulk I think the 12M we buy is $0.50/gal.


----------



## lanfear (Jun 12, 2015)

For those who are lucky enough to live in normal countries. 
I am from norway and the HCl is 56$ a gallon. :x
By the way, how can I set this thread as solved?

Jon


----------



## goldenchild (Jun 12, 2015)

Egh. It could literally be anything. Not worth the risk at all in my opinion. Who knows what else could be in it if it indeed has some HCL in it. I would say dispose of it properly. $56 dollars just isn't worth it.


----------



## artart47 (Jun 12, 2015)

Hi Friends!
Seeing how hydrochloric is dirt cheap, I wouldn't chance it. What if it's something with HF in it. You don't know! Or, did they dissolve something in it the could cause problems? Hg...etc ?

Be safe! artart47


----------



## Anonymous (Jun 12, 2015)

Silly thread guys. Throw it away and buy some HCl - it's not worth the risk messing about with an unknown solution. Honestly 8) 8) 8)


----------



## upcyclist (Oct 12, 2015)

I have a similar problem, but a different use. In my lapidary shop, the guy who owns the jewelry shop upstairs has a lot of old plating solutions stored in our area. I lovingly refer to it as "The Wall of Death" since many of the solutions are cyanide-based, and there's at least 10 pounds of dry(-ish) Sodium Cyanide. 

More to the point: about 15 of the bottles/jars/whatever are unidentified. I went through and checked everything with litmus paper, and for the sake of safety, I'm assuming everything alkaline is NaCN/KCN based. And unless it's noticeably oily/viscous, I'm assuming everything relatively pH-neutral is NaCN-based and old enough to have gone neutral 

For the acids, I'd like to ID them so I know how to handle them if they're gold-bearing (or otherwise positive with a stannous chloride test). I'm thinking of going with Kurt's simple tests, since the likely two are HCl & H2SO4:



kurtak said:


> A drop of sulfuric will result in a sputtering effect & HCl wont sputter - a drop of sulfuric on paper towel will eat the paper HCl wont



Does that sound sufficient? Or is it even necessary? Can I just process any gold-bearing acid solution the same way (i.e., precip with copper to precipitate PMs)? My main goal is to make it all safe, so if I can precip out the PMs and neutralize it without knowing what type of acid, I will. But I'm leery of purposely causing chemical reactions when I don't know what's in the bottle.


----------



## Anonymous (Oct 12, 2015)

Hi there upcyclist

If you already have some bottles that are known to be cyanide based, then treat the unmarked ones as potentially cyanide based until proven otherwise. I think your assumption that anything alkaline may be cyanide based is sound.


----------



## g_axelsson (Oct 12, 2015)

Some other simple tests for acids...

A drop of sulfuric acid into lead chloride solution precipitates lead sulfate. Only concentrated acid sputters and can be hard to see in just a few drops if you haven't seen it before.
Concentrated sulfuric is oily and very heavy.

A piece of silver will dissolve in nitric acid without any silver chloride formed. The formed silver nitrate can be used to detect chloride containing solutions, like hydrochloric acid.

A piece of copper will dissolve in nitric acid, but hydrochloric and sulfuric acid will just clean the surface from oxides, making it brighter.

If the bottles are clear, put it in the sun and in an hour you can see a pale brown-red gas above any nitric acid. That's NOx that is formed from the acid breaking down.

As pieces of copper or silver, use a wire that is easily just dipped ad the end to see the reaction and can easily be pulled up, cleaned and wiped off to do more testing.

Göran


----------



## upcyclist (Oct 13, 2015)

Thanks, guys.



g_axelsson said:


> A piece of silver will dissolve in nitric acid without any silver chloride formed. The formed silver nitrate can be used to detect chloride containing solutions, like hydrochloric acid.
> 
> ...
> 
> As pieces of copper or silver, use a wire that is easily just dipped ad the end to see the reaction and can easily be pulled up, cleaned and wiped off to do more testing.



Göran--the silver nitrate test is handy, but first I need to find a local NOx supplier that'll sell me something as small as a liter or half-liter to start out with, hehe (no point in buying gallons until I know for sure what quantities I'll use). Once I do, would a 100mg silver per 100ml solution ("standard solution") suffice? May as well kill two birds with one stone if I can!

The second bit about wire will be easy enough--as a silversmith & chainmailleur, I've got plenty of wire 

--Eric


----------



## Eamonn (Oct 13, 2015)

I hope its not Hydroflouric acid(HF). I dont know a simple test for HF.
If its in a glass container its not HF as HF eats glass.
You don't want this stuff around if you can help it. 
A drop on your skin will cause a nasty burn and dammage to your bones.


----------



## upcyclist (Oct 13, 2015)

Agreed--HF is evil stuff. Luckily, there's almost no reason for an electroplater to use it. To my knowledge, no one has ever done glass/enamel etching in that building. In jewelry/crafting circles at least, no one ever messes with HF unless they specifically need to eat glass. There's lots of cheaper and safer acids to choose from.

But yes, any unidentified low-pH stuff could be HF. Not likely, but possible.


----------



## g_axelsson (Oct 13, 2015)

The silver nitrate with hydrochloric acid reaction is very easily seen, any concentration works but when the concentration goes down it can be hard to see.

Göran


----------

