[palnm]

I wasn't sure where to share this problem/issue, but as I am taking some introduction chemistry courses, I felt this may be proper. When I came across a disinfectant solution I noted the ingredients within it. (Water (99.97%), Sodium Chloride (0.23%), Sodium Hypochlorite (0.004%), Hypochlorous acid (0.003%)). I thought that this may be an easy solution to create. However, I have run into an area of confusion. Sodium Hypochlorite is a main ingredient in bleach. However, when dissolved in water Sodium Hypochlorite dissociates into Hyprochlorous Acid (HOCl) and a Hypochlorite ion (OCl^-) [NaOCl + H2O → HOCl + NaOH^-]. On the same page it also said, "Sodium Hypochlorite is unstable. Chlorine evaporates at a rate of 0.75 gram active chlorine per day from the solution." I also read on the disinfectant that it was electrolyzed water. It was noted to me that soft water with, Sodium Chloride, when electrolyzed forms Sodium Hypochlorite solution.
 
So, first, how does Sodium Hypochlorite remain in solution? (ie. Why doesn't it just stay as the acid?) Or, does it not completely dissociate?

Is there anyway to increase shelf life? (Slow down rate of evaporation of chlorine?)

Could the ingredients just be the result of electrolyzed water?

I guess the real question is how to create a similar solution, while providing an explanation on how it results.

Also, could Hydrogen Peroxide be a substitute for Sodium Hypochlorite as a means for a disinfectant? If so, what are the concentrations and means of creating a similar substitute?

[Borek]

These are good questions, I am afraid they can be difficult to answer if you are just at the beginning of your intro course. Hypochlorite solutions are usually stabilized by adding sodium hydroxide, which increases pH, and shifts equilibrium of hypochlorite hydrolysis to the left. As it is hypochlorous acid that decomposes, keeping it in the form of OCl^- (and not in protonated form HOCl) slows the decomposition.

Also, I think your understanding of what is happening when you put sodium hypochlorite in water is incomplete. First, it dissociates:

NaOCl(s) -> Na⁺(aq) + OCl^-(aq)

Then, OCl^- reacts with water:

OCl^-(aq) + H₂O <-> HOCl(aq) + OH^-(aq)

While we can safely assume first reaction goes to completion (and NaOCl is 100% dissociated), the other one is in equilibrium - all substances listed are in the solution. Changing pH we can change concentration of OH^-, which in turn shifts equilibrium according to LeChatelier's principle.