Dried bleach crystals?

[evilwalnut]

I had a container with bleach, and at the end of a tube bleach has been slowly dripping out. I discovered a small puddle of bleach and lots of white crystals around the edgs and in the middle. Does anybody know what these are?

[budullewraagh]

those crystals are the monohydrate of sodium hypochlorite. it should be noted that these crystals are pretty unstable and can explode violently, especially if dessicated to the anhydrous salt. i would advise you to redissolve the crystals.

[woelen]

No, I don't think so that these are hypochlorite. I on-purpose made a lot of these crystals by letting some bleach evaporate in a petri dish. The crystals I obtained were mainly NaCl. The crystals, when dissolved in water again, hardly are oxidizing anymore and if HCl is added to them, no bubbles of chlorine are formed at all.

 

The reason for this is that solid NaClO.xH2O is very unstable. For this reason, solid NaClO is not available at all. Solid bleaches either are based on Ca(ClO)2 or LiClO or some chloroderivative of isocyanuric acid.

 

Indeed, the solid NaClO.xH2O is known, but it is a laboratory curiousity, which is not easy to make at all.

[budullewraagh]

i distilled bleach once to use in a chlorine-producing experiment and the solid produced plenty of Cl2 when mixed with HCl

[woelen]

Have a look of this page: http://en.wikipedia.org/wiki/Hypochlorite

 

It might be that you still had some NaClO3 in your dried sample. Chlorates give ClO2 with HCl and as the color of that gas is very intense, you might have regarded that as chlorine. Air with a few percents of ClO2 in it looks quite similar to pure Cl2 gas, albeit a little more yellow.

 

See also: http://woelen.scheikunde.net/science/chem/exps/clo2

 

Here you can see how ClO2 looks like in higher concentration, made from NaClO3.

[woelen]

I looked up one of my old books on synthesizing chemicals. Here is a method of making solid hydrated NaClO. The stuff definitely is not what you obtain by distilling bleach. The solid NaClO.5H2O melts at 18 C.

A scanned page of the book is included as attachment on this post.

 

This is a scanned page from the book "Handbook of preparative inorganic chemistry", by George Brauer, translated into English by Reed F. Riley. Academic Press, New York, 1963.

 

This is the kind of books from which I get my information and with the info from such books I already have made many interesting compounds. But NaClO.5H2O is beyond my reach .

[budullewraagh]

wow. that explains a whole lot. the gas evolved looked very similar to the ClO2/Cl2 mixture on your link. luckily i did the experiment at night so the minimal available light didn't detonate the ClO2. the solid left behind was pretty yellow and slightly orange.

[evilwalnut]

So the general consensus seems to be that these crystals are relatively harmless? Either way, the rain washed them away so its no longer a problem.

 

Thanks for all the help!

[akcapr]

Did i mention I evaporated bleach before and the "substance" left behind worked well for Cl synthesis with HCL.

[woelen]

Akcapr, read what is posted already in this thread. You did not have NaClO.

[akcapr]

wow. that explains a whole lot. the gas evolved looked very similar to the ClO2/Cl2 mixture on your link. luckily i did the experiment at night so the minimal available light didn't detonate the ClO2. the solid left behind was pretty yellow and slightly orange.

 

how come when i dried bleach then added HCL in daylight the gas didnt explode? With a alcohol lamp near

[woelen]

It is one of those urban legends that any amount of ClO2 explodes with the smallest amount of daylight. It can explode, when daylight hits ClO2, but this does not mean that it does explode. Besides that, ClO2 has a lower explosion limit of 10% gas by volume. An air/ClO2 mix with less than 10% ClO2 in it cannot explode.

Many people confuse an air-mix with a low concentration of ClO2 with pure chlorine. As you can see on my site, ClO2 has a very intense color, while Cl2 only has a weak color.

 

The mix I show on my website definitely can explode, that is why I tell to NOT stopper that test tube. An explosion then results in flowing of the gas out of the test tube (it only is a very small amount), otherwise the glass of the test tube may be shattered around.

[jdurg]

Indeed, Cl2 is a VERY pale color in regards to ClO2. When I made the chlorine gas in my element collection, the space right above where the Ca(OCl)2 and HCl met was a very intense color, but by the time the gas got through all of the purification steps we had setup (water, then anhydrous NaHCO3) it was barely visible. I couldn't even see the gas until we put a white cardboard sheet behind the collection tube and then we could see the green color. To this day, if I just hold my chlorine tube you really can't see the color when looking at it. If you turn the tube on its side and look at one end of it, however, the green color really shows up.

[woelen]

Well, it's not that pale... Have a look at this picture:

 

http://woelen.scheikunde.net/science/chem/compounds/chlorine.html

 

This is 300 ml of chlorine gas, made by adding dilute HCl to Ca(ClO)2 and leading the gas into this bottle. Quite some more Cl2 was made than this 300 ml, just to be sure that inside the bottle I almost have 100% pure Cl2. This gas, however, was not purified by bubbling it through water and drying it. So, it may contain some HCl and H2O, but these are not visible of course.

 

I never was brave enough to make this bottle full of ClO2 gas, it must be a wonderful thing to see, but I'm too afraid of a possible explosion .

 

Jdurg, did the chlorine gas become more pale, when you cleaned it with water and NaHCO3? That would be a very interesting phenomenon. Indeed, the gas is very pale, when viewed through a tube of 0.5'' width, but if you look at 3 inches of this gas, then it has a nice green color.

[jdurg]

I couldn't tell for sure if the decrease in color intensity was from optical differences or chemical differences. In the reaction vessel, the depth of the chamber was approximately 10 cm. In the tubes containing the water and NaHCO3, and eventually the vessel it is contained in, the diameter is only about 1.5 cm. So the difference in color intensity may be due to the depth of the viewing area. When I look at the tube from one end, it is a nice deep green like in your picture. It's when I see it from the side of the tube that it is nice and pale. In the picture you have, you have a large vessel so it is much easier to see the color. If you put some Cl2 in a thinner test tube, the color will be much less intense.

[KFC]

those crystals are the monohydrate of sodium hypochlorite. it should be noted that these crystals are pretty unstable and can explode violently, especially if dessicated to the anhydrous salt. i would advise you to redissolve the crystals.

 

 

 

hermal decomposition of hypochlorites

 

 

This is an alternative method of chlorate manufacture. It is more laborous than the electrolytic method, and can only be used for small batches at a time. The starting materials are quite easily available however as bleach and pool chlorinating agents and it only requires the use of simple tools.

3.1 Starting materials

 

 

Possible starting materials are sodium hypochlorite and calcium hypochlorite. The former is available in solution as bleach and antifungal spray for bathrooms. Calcium hypochlorite finds use as a chlorinating agent for pools. However, different varieties exist. Carefully read the package to make sure you have the right material. It usually states a '85% available chlorine' content for calcium hypochlorite. A higher available chlorine content may mean it is something else, most likely trichlorohydrocyanuric acid.

3.2 Method

 

 

Depending on the starting material, sodium or calcium hypochlorite, a different procedure must be followed. Each is described separately below.

 

Procedure when using sodium hypochlorite

 

It is assumed bleach will be used, which is usually a 4% solution of sodium hypochlorite in water. If a less or more concentrated solution is used, adjust the amounts accordingly.

 

1. Take 1 liter of bleach, and place this in heat resistant glass or stainless steel container. Bring it to a boil.

 

2. Boil the solution untill only about 140 ml of solution is left. The exact volume is not critical, a deviation of 10 to 20 ml is acceptable.

 

3. Allow the solution to cool. If crystals form upon cooling, filter the solution after it has completely cooled. The crystals are sodium chloride and can be discarded.

 

4. In a separate container, prepare a solution of potassium chloride. Dissolve 28 grams of potassium chloride in the smallest volume of water possible (about 80 ml). This can be done by dissolving the potassium chloride in about 90 ml of boiling water, and allowing it to cool. If crystals form, add some more water, boil again to dissolve the potassium chloride, and allow to cool again. If crystals form, repeat. If not, the solution is ready to use.

 

5. Mix the boiled bleach solution with the potassium chloride solution. A white precipitate should form. This is potassium chlorate.

 

6. Bring the solution to a boil and add water untill all potassium chlorate has dissolved.

 

7. Allow the solution to cool slowly. Crystals of potassium chlorate will form. Cool the solution to 0 deg C.

 

8. Filter to obtain the raw potassium chlorate. Rinse the crystals in the filter with ice-cold water. The product can be further purified as described below.

Procedure when using calcium hypochlorite

 

warning: On one occasion an small explosion occured when I was doing this preparation. I am not sure exactly what caused the explosion. It seems to have been a steam explosion. I was also not sure wheter I was using calcium hypochlorite or trichlorohydrocyanuric acid, another common pool chlorinating agent. It seems to be very uncommon that explosions happen and they can probably be prevented by vigorous stirring, but I thought everyone attempting this method should know so proper precautions can be taken. The procedure below has been optimised to reduce the chances of an explosion happening.

 

1. Place 250 ml of water in a heat resistant glass or stainless steel container, large enough to hold twice that volume.

 

2. Bring the water to a boil.

 

3. To the boiling water, add 125 gram of calcium hypochlorite in 10 gram portions. The calcium hypochlorite usually comes in tablets, which need to be crushed first. Stir vigorously during this step, occasionally scraping over the bottom to prevent the formation of a cake of calcium chloride. The solution will foam a lot. If too much foam is developed, do not add any more calcium hypochlorite and boil untill the foam subsides. Then continue adding calcium hypochlorite.

 

4. When all calcium hypochlorite has been added, continue boiling untill no more foaming is observed. Stir continuously.

 

5. Allow the solution to cool down, and filter to remove the precipitated calcium chloride.

 

6. In a separate container, dissolve 68 grams of potassium chloride in the smallest volume of water possible (approximately 195 ml). This can be done by dissolving the potassium chloride in about 200 ml of water, and allowing it to cool. If crystals form, add some more water, boil again to dissolve the potassium chloride, and allow to cool again. If crystals form, repeat. If not, the solution is ready to use.

 

7. Mix this solution with the boiled calcium hypochlorite solution. A white precipitate of potassium chlorate should form.

 

8. Bring the solution to a boil and add water untill all potassium chlorate has dissolved.

 

9. Allow the solution to cool slowly. Crystals of potassium chlorate will form. Cool to 0 deg C.

 

10. Filter to obtain the raw potassium chlorate. Rinse the crystals in the filter with ice-cold water. The product can be further purified as described below.

 

3.3 Purifying the product

 

 

The product can be purified by recrystallisation, just like the product of the electrolytic procedure. For convenience, the same procedure is given again here:

 

1. Place the crude product in a pan and add 100 ml of water for every 20 g of crude product. Bring this to a boil.

 

2. Add 20 ml amounts of water to the boiling solution untill all the potassium chlorate has dissolved.

 

3. Check the pH of the boiling solution. It should be neutral or slightly alcaline. If it is acidic, add potassium hydroxide solution untill it is slightly alcaline (pH 7..8) again. If this is not done, traces of acid may be included in the product making it very dangerous to use in pyrotechnic compositions.

 

4. Allow the solution to cool to room temperature. Potassium chlorate will crystalise.

 

5. Filter and rinse the crystals well with ice cold water. The filtrate may be discarded or concentrated by evaporation and the residue added to the electrolyte for a next batch.

 

6. The crystals may be dried in an oven at 100 deg C.

[KFC]

wow. that explains a whole lot. the gas evolved looked very similar to the ClO2/Cl2 mixture on your link. luckily i did the experiment at night so the minimal available light didn't detonate the ClO2. the solid left behind was pretty yellow and slightly orange.

 

I Carried Out An Experiment At This Site http://www.wfvisser.dds.nl/EN/chlorate_EN.html .I Don't Think I Got It Wright I Ended Up With Sulphur Color Solution Similar To Yours What Is This Solution And Is It Explosive And If It Isn't How Do I Make Explosive?

[Phi for All]

What Is This Solution And Is It Explosive And If It Isn't How Do I Make Explosive?

This forum doesn't publish how to make explosives. Too many people might get hurt and it is our policy to avoid helping them do that.

 

Don't ask again.

[KFC]

Oh, Sorry

Well Then What Was The Sulution .

 

P.S.

I Used Copper And Graphite Electodes.

[woelen]

The yellow color probably is due to dissolved ClO2. That gas, when dissolved in water, gives a very intense yellow/green color to the solution.

[KFC]

I Took A Look At The Solution To Day And There Is Sediment That Is Yellowy Orange Like Orange Juice Yellow And There Is A liquid That Is Clear above It.

[KFC]

I Took A Look At The Solution To Day And There Is Sediment That Is Yellowy Orange Like Orange Juice Yellow And There Is A liquid That Is Clear above It.

 

 

Heres I picture:

 

[KFC]

Sorry The Camera Is Blurry But What Is The Sediment And WHat Do You Think The liquid Is ?

[woelen]

Ah, that picture makes things more clear. You used copper electrodes with this, otherwise you would not have this orange material.

 

This orange stuff mainly is Cu2O (copper (I) oxide). It is formed by the oxidation of copper at the anode (Cu + 2Cl(-) --> CuCl2(-) + e), the e taken up by the anode.

 

CuCl2(-) in turn reacts with hydroxide, formed at the cathode:

 

2CuCl2(-) + 2OH(-) --> Cu2O + H2O + 4Cl(-)