Thinking about Active Chlorine

[TreeFiter]

Thinking back to my original posts regarding an experiment, I'm wondering if instead of relying on smell, I could look at the bleaching ability of the solution. Maybe take two identical T-shirts and put them into the solutions, and after a few days or even weeks, compare how faded they are. My hypothesis here would be that the solution with very high FC, and high CYA would have less bleaching effect than the solution with lower FC, but no CYA.

If I used a closed system, like a jar with an air tight lid, could I expect FC levels to remain fairly stable, or will I lose FC due to sunlight? The Chlorine has nowhere to go, but it might be converted to a less effective form. Any thoughts?

 

[chem geek]

The odor of chlorine and of chloramines is a bit different. In fact, depending on where the chlorine lands and reacts, you can get somewhat different smells. See Bleach Hand Smell, for example.

As for smelling bleach in the bottle, be very careful. The narrow opening can be deceiving. Do not put your nose to it or you can get a much too strong whiff. Use your hand to whisk the air from the opening towards your nose.

 

[JasonLion]

When chlorine breaks down ammonia, or any of several other nitrogen compounds, it reacts in two or more stages. First one (or more) chlorine(s) binds to the nitrogen compound, creating combined chlorine. When enough chlorine has bound, a final chlorine breaks the compound apart. The final products are typically salt, water, and nitrogen gas.

Binding the first chlorine to create combined chlorine tends to go fairly quickly, while the later reactions go more slowly. In some cases excess CC can build up, especially if the amount of chlorine available is very limited. By keeping the FC levels appropriately high, we maximize the speed for the final reactions, keeping the CC levels as close to zero as possible.

Chlorine is very reactive and will breakdown even in a closed system. The rate will vary depending on conditions, but it does break down eventually regardless.

 

[chem geek]

Concentrated chlorine (hypochlorite) breaks down even in the dark and this breakdown is accelerated with metals. You can read more about this in this link. Roughly speaking, the breakdown increases with the square of the chlorine concentration and also increases with temperature.