Ingredients of Household Bleach

Sodium hypochlorite - Wikipedia, the free encyclopedia

"you get hypochlorous acid HOCl and caustic soda NaOH"

HOCL is an acid and NaOH is a base. How can they co-exist in the same container as such? They will react and salt would be a product of reaction.

If you add water to Sodium Hypo solution, it will only get diluted and would not have a chemical reaction.

Sodium Hypo is produced by adding (dissolving) controlled amount of Chlorine to dilute caustic solution. This is an exothermic reaction and reaction temperature has to be controlled.

Here is a very old paper on Dakin's Solution. I think it describes the stability very well and is still apt today. Enjoy.

Thank you for your answers.
You helped me a lot. After surfing the web, consulting some books and carefully reading what you wrote, I came to conclusion:
Sodium hypochlorite disociate to Na+ and OCl- ions in water. If solution is acidic (ph<7) folowing reaction starts: Ocl- + H2O = HOCl + OH-. Futher decomposition happens:
3HOCl = HClO3 + 2HCl
and finally HOCl + HCl = H2O + Cl2
So finally we have highly corrosive Cl2 needed for disinfection.
In order to start that chain of reactions, the solution has to be acidic. Acidity of solution we achieve by mixing bleach with lot of water. In order to prevent this from happening during shelf life of bleach, sodium hydroxide NaOH is added to bleach, which increases pH value of bleach thus preventing those reactions

Thank you very much for your answer, but can you please comment information from following link

http://www.lenntech.com/processes/disinfection/chemical/disinfectants-chlorine.htm

Thanks in advance,

As others have pointed out, a little chemistry knowledge can be a dangerous thing. You do not want to acidify the solution, because this will form gaseous Cl2, which will leave the solution (and is very dangerous to breath).

The article is strictly not correct. It is highly simplified for the average reader. Yes, Cl2 is widely used for disinfection, but only when dissolved. When it dissolves, it forms HOCl and OCl- ions, the same as NaOCl does. Strictly speaking, it is the OCl- ion that does the disinfection. Dry CL2 would have little sanitizing power.

If you Google sodium hypochlorite and sanitizer you will get a better feel, including appropriate Ph levels for sanitation. But, I I highly recommend that you consult with someone that is knowledgeable in this field.

GA

The wrong conclusion by the OP is exactly why I tried to emphasize that a formal collegiate education is required to really understand which reactions will happen at what pressures and temperature. Many introductory Chemistry classes just handle the balancing of reagents in a stoichiometry relation. To discern which possible set of reagents will actually occur, one must also include the energy applied or released for the reaction to occur. A major part of this is understanding how to use the electro-negativity of the elements involved, the dipole moments of the molecules involved and sometimes even the three dimensional nature of all of the reactants.

Chemistry is one of the fields that personifies the phrase "A little knowledge is dangerous."

Sorry, not a great answer.

If you acidify a NaOCl solution with HCl, Cl2 gas will be given off. It is a reversible reaction.

Your explanation of the formation and dissociation of NaOCl is not totally correct.

Concentrating the NaOCl will result in a more aggressive oxidizer, but the real danger in attempting to concentrate a NaOCL solution is that it contains traces of NaOCl3, which is explosive. It is correct that both NaOcl and Ca(OCl)2 can be dried to a powder, and 0CL- is the ion which does do the disinfection.

Your general summary is correct, however, the OP has come to the wrong conclusion.

GA. OP best be careful he doesn't form Cl2

It is easily made by the electrolysis of common-salt brine, though the process does liberate hydrogen, which is flammable.

Water softener grade salt should be used for this electrolysis, as common "table salt" contains anti-caking agents that get in the way.

It might be worthwhile to go back to the fundamentals and study up on Le Cahtelier's principle and understand the equilibrium state of the solution.