Sciencemadness Discussion Board - Found an easy way to make chlorine gas from muriatic acid and bleach

Found an easy way to make chlorine gas from muriatic acid and bleach

Cou - 20-5-2013 at 13:11

I found out you can make chlorine gas by mixing hydrochloric acid with clorox or bleach in a bottle. Since muriatic acid is more accessible from stores than sulfuric acid, this is a great way to make it if you didn't know about it. Just pour a small amount of HCl in a bottle, crush the bottle to get most of the air out, then pour the same amount of bleach in it. Quickly tighten the cap, shake the bottle around, and it turns green from the gas! Just keep the cap on tight; one time I forgot to put it on, the chlorine smells horrible and I had a headache and nausea the rest of the day. Reminded me of the city swimming pool, they put way too much chlorine in there

I plan to do an iron and chlorine reaction with it, once I get a bunsen burner and a florence flask.

[Edited on 20-5-2013 by Cou]

[Edited on 20-5-2013 by Cou]

[Edited on 20-5-2013 by Cou]

Mixell - 20-5-2013 at 13:15

Thank you captain.

simba - 20-5-2013 at 13:17

Sorry to burst your bubble, but that really isn't anything new, you can make it from calcium hypochlorite or TCAA aswell, which is even better in fact.

[Edited on 20-5-2013 by simba]

Cou - 20-5-2013 at 13:43

What is the balanced equation for this?

Chemistrium - 20-5-2013 at 13:53

HClO + HCl --> H2O + Cl2

Pyro - 20-5-2013 at 14:01

NaClO+2HCl->NaCl+Cl2+H2O
bleach is NaClO or sodium hypochlorite.

Chemistrium - 20-5-2013 at 14:04

Oops I forgot about that

Cou - 20-5-2013 at 14:26

This is really cool though... now i don't have to go to Airgas and buy chlorine! But why is it the bottle was only faint green, then when I opened it and let the pressure out, the chlorine turned cloudy and opaque green? Also there is a solution of chlorine in water at the bottom of the bottle, but it's probably just not coming out because the bottle is full

woelen - 20-5-2013 at 23:50

Do I understand that you prepare the chlorine in a closed bottle? Be careful with that, if you mix too much of the chemicals, you'll build up a lot of pressure and then the bottle may explode! You do not want glass shrapnel flying around or into your head!

If you prepare chlorine, then pour some bleach in the bottle and then pour acid in the bottle and leave the bottle open. Once the production of gas has (nearly) ceased, then cap the bottle.

The cloudiness of the chlorine on pressure release is a well-known effect. The same thing you see when you open a bottle of soda water, coca cola or beer. The pressurized gas above the liquid expands at once and cools down. Water vapor in the gas then condenses and forms a cloud of small water droplets.

Finnnicus - 21-5-2013 at 00:37

Woelen, the BP of chlorine is ~-34C so can you explain better (a) newb(s) like me?

woelen - 21-5-2013 at 01:18

If you have a chemical reaction in which a compound is formed, which has a boiling point (much) lower than the ambient temperature, then that compound escapes as gas. This happens with chlorine as well. The liquid you have I expect to be somewhere around 20 C, so any chlorine which is formed escapes as a gas.

There is a little complication here. Chlorine dissolves quite well in water. Appr. 3 liter of gas dissolves in 1 liter of water of room temperature. The solubility in water also depends on pressure. The higher the pressure, the better the gas dissolves in water. But still, more chlorine is produced than what can dissolve in water, and hence bubbles of gas escape from the liquid.

Another property of gasses is that when a certain amount of gas is compressed into a smaller volume, it heats up and if a certain amount of gas is allowed to occupy a large amount of space, then it cools down. This effect occurs for all gases, it does not depend on the chemistry, but it a purely physical phenomenon. The cooling down on expansion of the gas can be so strong that water vapor in the gas (which is present to saturation in this chlorine experiment, but also in coca cola bottles) condenses to small droplets.

Finnnicus - 21-5-2013 at 05:05

Thank you, I did know that, but *helping!*. So the bit that confused me was the chlorine escaping from Cou's sealed bottle through this pressure temperature mechanism reached -34C??? The ideal gas law doesn't help to much here ((gives me a temp of ~-12)though I don't know the volume of cau's bottle)... I need to learn more!
Sorry for simple questions.

AJKOER - 21-5-2013 at 06:02

I would add a slightly more advanced comment at this point. A gas cannot only dissolve in water, it can undergo a chemical reaction, for example, hydrolysis. In the case of chlorine, Cl2:

Cl2 + H2O <---> HCl + HOCl

that is, a reversible reaction forming Hydrochloric acid and Hypochlorous acid in the case of Chlorine water. Now, the latter acid is unstable and to quote from Wikipedia on Hypochlorous acid (http://en.wikipedia.org/wiki/HClO):

"The presence of light or transition metal oxides of copper, nickel, or cobalt accelerates the exothermic decomposition [of Hypochlorous acid] into hydrochloric acid and oxygen:[9]"

So in the presence of say CuO, the reaction above would no longer be reversible, and would move to the right as follows with the release of Oxygen gas:

2 Cl2 + 2 H2O → 4 HCl + O2

Another derivative of Chlorine, Chlorine dioxide is much more soluble than Cl2, but unlike Chlorine the hydrolysis reaction is far to the left:

ClO2 + H2O <<----> HClO2 + HClO3

In other words, Chlorine dioxide is behaving more as an inert gas in water, and can, in fact, be rapidly displaced from solution with the addition of say CO2, which is not the case for Chlorine (Source: Please see page 4-2 at http://www.google.com/url?sa=t&rct=j&q=hydrolysis%20... )

[Edited on 21-5-2013 by AJKOER]

Bot0nist - 21-5-2013 at 06:03

Quote: Originally posted by Finnnicus

Thank you, I did know that, but *helping!*. So the bit that confused me was the chlorine escaping from Cou's sealed bottle through this pressure temperature mechanism reached -34C??? The ideal gas law doesn't help to much here ((gives me a temp of ~-12)though I don't know the volume of cau's bottle)... I need to learn more!
Sorry for simple questions.

I'm not sure if I am following you, but the chlorine is not condensing into droplets when released from pressure. The expanding gas cools down and any mixed water vapor in the gaseous chlorine begins to form tiny aerosol. This makes the escaping gas more opaque. At least that is my simple understanding. I highly doubt the expanding chlorine is dipping to -34C...

MrHomeScientist - 21-5-2013 at 07:21

Right, we aren't talking about liquid chlorine here - you'd need quite a lot more expansion (or equivalently a lot more pressure in the original container) to lower the temperature that much. The reaction produces chlorine gas above an aqueous solution, which also means that a lot of water vapor will be present. When these gases escape, they cool enough where the water vapor can condense into a cloud of liquid water droplets. The chlorine probably dissolves in these to some extent, but would itself remain a gas (unless it hydrolyzes and reacts into something else).

blogfast25 - 21-5-2013 at 09:57

Quote: Originally posted by Finnnicus

The ideal gas law doesn't help to much here ((gives me a temp of ~-12)though I don't know the volume of cau's bottle)... I need to learn more!

No, it doesn't: you're quite far removed from ideal gas conditions; low temperature with water vapour thrown in too. Only at higher temperatures would such a mixture start behaving according to pV = nRT. Although the broad lines of gases cooling on expansion (e.g.) still hold, of course.

[Edited on 21-5-2013 by blogfast25]

[Edited on 21-5-2013 by blogfast25]

Nitro-esteban - 27-8-2013 at 17:06

I think there are 2 reactions:
NaClO + HCl = NaCl + HClO.
HClO + HCl = Cl2 + H2O.

phlogiston - 28-8-2013 at 05:03

In solution, the sodium hypochlorite is fully ionized, so for the purposes of describing the mechanism of the reaction, it does not make sense to use 'NaClO' or 'NaCl' in the equations. There is only Na<sup>+</sup> (which does not participate in the relevant reactions) and ClO<sup>-</sup>.

However, hypochlorous acid is a weak acid, so there can be HClO in the solution (in a certain pH range).

[Edited on 28-8-2013 by phlogiston]

MrTechGuy1995 - 28-8-2013 at 05:39

I actually used this many times, but instead, I put a hole in the cap. Then put a small hose, preferably PP tubing so you don't get degradation.

Then I fill what ever vessel I have with the needed chlorine, and when the reaction is done, I'd cap the bottle tightly, and throw it away.

Calcium Hypochloride, or TCCA with HCl will work better.

I would recommend some kind of holder for the reaction bottle, because the bottle will like to tip over cause of the hose.

Feel free to tell me how dumb I am, or how environmental I am with how I dispose of it.

[Edited on 28-8-2013 by MrTechGuy1995]

Magpie - 28-8-2013 at 07:42

When stating that a gas expands when it cools some mention of the Joule-Thompson effect is in order I think since an ideal gas does not cool on expansion. Here's an excerpt from Wiki:

Joule–Thomson effect: In thermodynamics, the Joule–Thomson effect or Joule–Kelvin effect or Kelvin–Joule effect or Joule–Thomson expansion describes the temperature change of a gas or liquid when it is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the environment. This procedure is called a throttling process or Joule–Thomson process. At room temperature, all gases except hydrogen, helium and neon cool upon expansion by the Joule–Thomson process. The effect is named for James Prescott Joule and William Thomson, 1st Baron Kelvin, who discovered it in 1852 following earlier work by Joule on Joule expansion, in which a gas undergoes free expansion in a vacuum. In the Joule experiment, the gas expands in a vacuum and the temperature drop of the system is zero, if the gas were ideal. The throttling process is of the highest technical importance. It is at the heart of thermal machines such as refrigerators, air conditioners, heat pumps, and liquefiers. Furthermore, throttling is a fundamentally irreversible process. The throttling due to the flow resistance in supply lines, heat exchangers, regenerators, and other components of (thermal) machines is a source of losses that limits the performance.

AJKOER - 28-8-2013 at 10:06

Actually, here is a more useful way (actually, it makes the so-called bleach battery that you can use to produce electricity as well) to make some Chlorine. Steps:

1. Mix bleach (NaOCl) and vinegar (which contains Acetic acid HAc) in the volume ratio 1.4 parts of 5% vinegar to one part of 8.25% extra strength chlorine bleach.

2. Add a piece of copper metal which will function as the cathode.

3. Add an Aluminum source to act as the anode (finely cut up Al foil, for example, will also work).

4. Add a touch of sea salt (better than NaCl) to act as the electrolyte to get things started.

My take on the chemistry:

The creation of Hypochlorous acid:

NaOCl + HAc --> HOCl + NaAC

And, on the major electrochemical reactions:

H2O <--> H3O + OH-

At anode: Al + 3OH- ⇒ Al(OH)3 + 3e-

At the cathode (copper):

3 HOCl + 3 H3O+ + 3 e- ⇒ 3/2 Cl2(g) + 3 H2O

for an implied net reaction of:

3 HOCl + Al --> Al(OH)3 (s) + 3/2 Cl2 (g) Eo net = 3.93 V

This battery cell is theoretically capable of generating 3.93 volts.

Reference: see http://www.exo.net/~pauld/saltwater/ and http://sci-toys.com/scitoys/scitoys/echem/batteries/batterie... and also http://www.dtic.mil/dtic/tr/fulltext/u2/d019917.pdf

There are also many side reactions. For safety, however, it should be noted that in addition to the toxic/corrosive Chlorine gas, in the case of the use of an excess of Aluminum, some explosive hydrogen gas can also be formed (in about a day) as the protective Al2O3 coating is attacked in a salt solution permitting the reaction:

2 Al + 6 H2O --> 2 Al(OH)3 + 3 H2 (g)

[Edited on 28-8-2013 by AJKOER]

Cou - 28-8-2013 at 13:27

Quote: Originally posted by AJKOER

Actually, here is a more useful way (actually, it makes the so-called bleach battery that you can use to produce electricity as well) to make some Chlorine. Steps:

1. Mix bleach (NaOCl) and vinegar (which contains Acetic acid HAc) in the volume ratio 1.4 parts of 5% vinegar to one part of 8.25% extra strength chlorine bleach.

2. Add a piece of copper metal which will function as the cathode.

3. Add an Aluminum source to act as the anode (finely cut up Al foil, for example, will also work).

4. Add a touch of sea salt (better than NaCl) to act as the electrolyte to get things started.

My take on the chemistry:

The creation of Hypochlorous acid:

NaOCl + HAc --> HOCl + NaAC

And, on the major electrochemical reactions:

H2O <--> H3O + OH-

At anode: Al + 3OH- ⇒ Al(OH)3 + 3e-

At the cathode (copper):

3 HOCl + 3 H3O+ + 3 e- ⇒ 3/2 Cl2(g) + 3 H2O

for an implied net reaction of:

3 HOCl + Al --> Al(OH)3 (s) + 3/2 Cl2 (g) Eo net = 3.93 V

This battery cell is theoretically capable of generating 3.93 volts.

Reference: http://sci-toys.com/scitoys/scitoys/echem/batteries/batterie...

See also http://www.dtic.mil/dtic/tr/fulltext/u2/d019917.pdf

There are also many side reactions. For safety, however, it should be noted that in addition to the toxic/corrosive Chlorine gas, in the case of the use of an excess of Aluminum, some explosive hydrogen gas can also be formed (in about a day) as the protective Al2O3 coating is attacked in a salt solution permitting the reaction:

2 Al + 6 H2O --> 2 Al(OH)3 + 3 H2 (g)

[Edited on 28-8-2013 by AJKOER]

If this doesn't use a battery, would I just connect the copper and aluminum electrodes with a wire, and it works automatically? And do you collect the chlorine by putting the copper electrode under an upside down jar filled with water?

Cou - 28-8-2013 at 14:00

Also can i use glacial acetic acid>

AJKOER - 28-8-2013 at 14:40

To be honest, while having performed the above experiment with Aluminum flakes, I did not use a solid Al anode with wires connected.

Sadly, I do not have the equipment to test current output from the hypochlorite Aluminum/Copper battery.

As a point of information, I did test the formation of H2 gas with excess use of Aluminum with a flame and was greeted with a loud retort (and, on another occasion a retort and a hot blue flame). Apparently, as it is well know, H2 and Cl2 (or O2) can form a kinetically powerful explosion. If you decide to test the gas mixture similarly, take safety precautions.

Also, while there are demonstrations of a uv light initiated explosion of H2 and Cl2 on the web, fortunately per my research, this is not too likely here (well, at least, in my humble opinion) as any O2 presence has a powerful spoiling effect on a light initiated detonation. It may be possible, however, that one could open a closed reaction vessel and vent out all air leaving just the heavy Cl2 gas and reseal allowing further H2 generation. However, any significant O2 formation via the photolysis of Hypochlorous acid via:

2 HOCl --> 2 HCl + O2

could again present a spoiling issue. Ignoring this, in a very thin walled transparent container, uv rays may be able to cause an explosion.
---------------------------------------------

Hypochlorous acid is formed by the action of a weak acid (like Acetic, Boric, or even slowly with H2CO3), or with a very dilute mineral acid. Also, per the author in my first reference, even very small concentrations of HOCl found in Bleach will react. As such, focus on weak acids as strong acid form Cl2 gas with Chlorine bleach (which contain NaOCl/NaCl... as a result of the formation of the hypochlorite by the action of Cl2 on hot concentrated aqueous NaOH) via the reaction sequence, for example with concentrated Sulfuric acid:

NaOCl + H2SO4 --> NaHSO4 + HOCl

NaCl + H2SO4 --> NaHSO4 + HCl

HCl + HOCl = Cl2 + H2O

[Edited on 29-8-2013 by AJKOER]

Cou - 31-8-2013 at 20:35

I don't think that would work because chlorine is so soluble in water, compared to air, so the chlorine bubbles would dissolve in the liquid before they got to the top of the test tube. Depends on how fast the chlorine is created, so it has time to rise before it dissolves.

Does the aluminum have to be finely cut up, or can you use one giant aluminum electrode

[Edited on 1-9-2013 by Cou]

blogfast25 - 1-9-2013 at 05:40

Quote: Originally posted by Cou

I don't think that would work because chlorine is so soluble in water, [Edited on 1-9-2013 by Cou]

Solubility in water isn't that great: acc. Wiki in STP about 1.125 L of Cl₂ per 1 L of water. That's about 0.05 mole/L. Once the solution is saturated with chlorine, any 'excess' chlorine will of course escape.

AJKOER - 4-9-2013 at 12:19

I agree that this is not a classic quick (forceful) chlorine generation tool. It may, however, be a gradual long lasting method for some applications. Note, there is quickly an evident chlorine smell, so perform this experiment in a sealed chamber or outdoors.

Some Chlorine probably reacts with water as follows:

Cl2 + H2O <-----> HCl + HOCl

, which is not completely a bad thing as more hypochlorous acid will fuel the battery and eventually form more Cl2 and Al(OH)3. In addition, the following reaction could move the above reaction to the right:

3 HCl + Al(OH)3 ---> AlCl3 + 3 H2O

, but to a lesser extent if the copper anode is not in contact with the jelly like clear Aluminum hydroxide (which resides at the bottom of the battery cell).

Heating the solution should help drive off any unreacted chlorine.

Bottomline, not a great path to rapid, or possibly abundant chlorine generation (due to secondary reactions), but does have interesting side products.
-----------------------------------------------------------

[EDIT] I repeated the experiment, using an old pre-1982 penny, which is brass, 95% copper, 5% zinc (please see http://en.wikipedia.org/wiki/Penny_(United_States_coin) ) and added no NaCl to the solution this time (the Cu/Zn alloy is apparently more reactive than pure Cu). I also moved the copper anode to be near the top of the battery cell.

Now, Chlorine is formed at the copper cathode with hopefully reduced solution contact by the reaction :

3 HOCl + 3 H3O+ + 3 e- ⇒ 3/2 Cl2(g) + 3 H2O

and today I noticed more solids suspended in the solute with a tint of green. I suspect the formation of some copper hydroxychloride, Cu(OH)2.CuCl, which exists as a greenish insoluble solid in near neutral solutions (see http://en.wikipedia.org/wiki/Copper_oxychloride ). I also observed possibly more Chlorine generation as there was as an obvious gas buildup. Now, this is most likely not entirely H2 given the rapidity of its creation and the avoidance of employing any excess Aluminum (the Al was completely dissolved in the first few hours).

I wish to thank Cou for his comment as the source of the inspiration to move the copper cathode to a higher position in the battery cell. It appears to have increased Cl2 output and created a more visible alternate oxychloride.
---------------------------------------------------

My speculation, on the formation of the Copper oxychloride.

Cu + 2 OH- ---> Cu(OH)2

Cl2 + H2O = HCl + HOCl

Cu(OH)2 + 2 HCl = CuCl2 + 2 H2O

Then, per Wikipedia, equation (3), for example, at http://en.wikipedia.org/wiki/Copper_oxychloride

2CuCl2 + 3 OH- → Cu2(OH)3Cl + 3 Cl-

Interestingly, the formation of Cu(OH)2.CuCl may limit the creation of the insoluble Al(OH)3. In addition, the reaction of any formed Aluminum hydroxide with the chloride ion could form an Aluminum oxychloride.

[Edited on 5-9-2013 by AJKOER]

Plutonium239 - 4-9-2013 at 13:39

I just did this last night. So much chlorine was produced that the stopper on my flask was blown off, but it all turned out well. Now I have a really cool sample of chlorine.

AJKOER - 6-9-2013 at 04:23

Plutonium239:

I hope that you did not employ an excess of Acetic acid relative to the Bleach in the formation of the Hypochlorous acid for the Bleach battery cell.

My concerns reside with a potential formation of Chloroacetic acid, ClCH2CO2H, in the Bleach cell with excess Acetic acid undergoing chlorination. While this acid is usually created in the presence of Acetic anhydride, I would not rule out its formation entirely.

To quote Wikipedia (http://en.wikipedia.org/wiki/Chloroacetic_acid ):

"The predominant method involves chlorination of acetic acid:

CH3CO2H + Cl2 → ClCH2CO2H + HCl

Acetic anhydride serves as a catalyst for this reaction."

As Chloroacetic acid is toxic, an alkylating agent (see http://en.wikipedia.org/wiki/Alkylating_agent#Alkylating_age... ) and a strong acid (pKa 2.85), I would strongly advise employing a stoichiometric excess of Bleach relative to vinegar to avoid its possible creation upon chlorination. One could also prepare HOCl by the action of an alternate weak acid (Ascorbic, Boric, ....) on NaOCl.

[Edited on 6-9-2013 by AJKOER]