# Making chlorine gas with HCl & KMnO4

1. ### thunderfvck

209
Hi.
I was reading how to make chlorine gas from HCl and KMnO4. KMnO4 is added to a round bottom flask and then HCL is added via an addition funnel at a pretty slow rate. THe gas is directed into a container with water (through a tube), a bubbler he calls it, it has an in tube and an out tube. This bubbler ensures that the HCl (unreacted I guess) dissolves in the water, right? While the Cl2 is insoluble in water and passes through the out tube, is this correct?
Okay, a couple of questions. 2 molecules of MnO4- are needed to strip 2 hydrogens off HCl, and the two Cl's combine and become the diatomic Cl2. Is this correct?
This reaction calls for muriatic acid, which is something like 31.5% HCl. It's OTC, and I was wondering if anyone knew the brand name of this product, or is it simply sold as muriatic acid?
I was also reading that KMnO4 can be purchased from a petshop store as an anti-bacterial agent to be used in pond treatment. I'm guessing this stuff isn't 99.9% pure, probably somehting like 70%, but for the purpose of this experiment would this be suitable? Thanks.
BTW, I know Cl2 is a nasty gas and I know of the risks involved, this would be an experiment I probably wouldn't be doing inside (especially since I don't have a fume hood).
Thanks again!

Last edited: Jan 18, 2004
2. ### ShawnD

953
You are correct about both products, they can easily be purchased over the counter like that. The muriatic acid is a common name, not a trademark name; several brands make it.
The OTC products should do just fine, they're pretty much only water and whatever chemical you want. The water shouldn't do anything negative in the reaction.

That reaction sounds very possible. My redox table says the reactions look like this:

$$2MnO_4^- + 16H^+ + 10Cl^- --> 2Mn^2^+ + 8H_2O + 5Cl_2$$

Good luck with the experiment

Last edited: Jan 18, 2004
3. ### thunderfvck

209
Oh So Mn2+ is formed, does it exist as a free ion in solution?
Would you happen to know a tradename for muriatic acid?
Thanks

and what is this redox table you speak of, can you offer a link?

4. ### ShawnD

953
It's from highschool. Here's a copy of it.

redox table

It's a useful table.....if you know how to read it

5. ### thunderfvck

209
To hell with the KMnO4! Just use NaOCl, bleach!

2HCl + NaOCl --> Cl2 + NaCl + H2O

So that's why they mention on the bottle of Javel that it shouldn't be mixed with acid...may form a corrosive gas. Ahhhh, okay. Chlorine really stinks. I did the reaction in this huge 4L flask and man that stuff is potent. I was hoping for some crazy green gas to form but I didn't notice anything like that. Probably because the reaction was on a small scale, I didn't want to gas myself to death. It was very exciting though. And I finally got some muriatic acid! Yay, it was cheap. I got 4L of it for like \$10, 31.45% HCl.

6. ### Monique

4,445
Staff Emeritus
[?] sometimes I really don't understand people.. someone is gonna get hurt sometime..

7. ### thunderfvck

209
Oh it's bound to happen one day.
But considering the conditions I ran the experiement under I don't think it was such a deadly risk. I had a huge container to contain the reaction and used a couple of ml's of each reactant. So you see, I wasn't threatening my life or anything. But as I get older and more experienced I'm bound to run into greater potential dangers. Like peroxides in ether. That stuff scares me. But I read read read and I know not to mess around too much with nature.
A few years ago I did some really nasty stuff, I'm sure we all went through the chemistry of explosives phase. Some more than others. Anyway, I wasn't too bad, but I used to put some pool chlorine in a 2L bottle and added some milk. Then I shook it up real good and threw it as far away as possible. Then I ran like a bastard. BOOM. Big explosion, I swear it sounded like a shotgun went off. That was dangerous. Very stupid and very dangerous.
Anyone have any idea what reaction took place?

8. ### Monique

4,445
Staff Emeritus
Well, here in the Netherlands lots of people get hurt each year during new years festivities when they mess around with fireworks.. it is very unfortunate to hear people die or get hurt because of stupidities..

9. ### Hurkyl

15,998
Staff Emeritus
Quick quiz:

How much gas would just a couple mLs of reactant make?
Does chlorine gas dissipate quickly, or linger near the ground?
What sort of dosage is lethal?
What sort of dosage can cause severe reactions?
How quickly can you tell if you've been inhaling it?

10. ### Monique

4,445
Staff Emeritus
A proper scientist (aka experimentalist) would now such data before running an experiment.. so.. thunderfvck, did you do the research beforehand?

May I add: what should be done upon exposure to skin or inhalation.
Do you perform the experiments alone?

11. ### shrumeo

250
The reason you didn't see any gas is because almost all of it remained dissolved in the water. I'm sure the smell knocked you on your butt, though.

When doing something that will produce Cl2 gas, if you are not careful you might really hurt someone.

12. ### thunderfvck

209
I really didn't consider what I did a serious risk given the amount I had reacted. I can't answer your questions Hurkyl without doing the calculations and I'd really prefer not to because I feel that a couple of millilitres of reactants would not do me any serious harm. I didn't do any serious research beforehand, it was a kind of spur of the moment thing. I just bought the HCl, the first REAL chemical I have ever purchased, I was pretty excited about it all. I wanted to do some kind of reaction.I was aware that chlorine gas islethal at certain concentrations but, again, I felt that the couple ml's wasn't going to produce enough Cl2 for a death dose. The reaction was also contained in a 4L flat bottomed flask, so most of the gas remained inside of the flask and didn't pass through the neck. Besides which I didn't have my face right above the opening, I wasn't huffing the gas as it was being formed. I did however catch a wiff when I was cleaning the flask out with water, and that prompted me to hold my breath while I finished up. It was a powerful bog stentch.

I may have not been super safe about it all but I did take certain precautions and I was sure that they were adequate for my safety.

I appreciate you guys making me look like a careless idiot though, that was really beautiful. haha. I joke. I made myself look like the idiot and I don't need your help, thank you.

13. ### Monique

4,445
Staff Emeritus
Acute: Low concentrations of chlorine can cause itching and burning of the eyes, nose, throat and respiratory tract. At high concentrations chlorine is a respiratory poison. Irritant effects become severe and may be accompanied by tearing of the eyes, headache, coughing, hoking, chest pain, shortness of breath, dizziness, nausea, vomiting, unconsciousness and death. Bronchitis and accumulation of fluid in the lungs (chemical pneumonia) may occur hours after exposure to high levels. Liquid as well as vapor contact can cause irritation, burns and blisters. Ingestion can cause nausea and severe burns of the mouth, esophagus and stomach.