What is bleach?

Question

Where does it come from? Does it harm waste-water treatment plants? How does it work? Did old timey people have it? When was it invented?

Answer 1

The chemical name for bleach is Sodium hypochlorite or NaClO. Like all hypochlorites, sodium hypochlorite is a salt of hypochlorous acid, HClO.

In water, it partially splits into the sodium cation Na+ and the hypochlorite anion ClO−, while a substantial portion hydrolyses into sodium hydroxide and hypochlorous acid. The oxidizing power of the latter and of the hypochlorite anion cause the bleaching effect. The hypochlorite anion's negative charge, however, prevents it from diffusing through the cell walls of
bacteria and microbes, making it a poor disinfectant. However, the hypochlorous acid molecules that exist in equilibrium with the hypochlorite anion, due to their neutral charge and small size, easily diffuse through the cell walls of bacteria. Its inactivation effectively destroys the micro-organism's ability to function.

Sodium hypochlorite is a strong oxidizer. Products of the oxidation reactions are corrosive. Solutions burn skin and cause eye damage, particularly when used in concentrated forms. However, only solutions containing more than 40% sodium hypochlorite by weight are considered hazardous.

Plants and animals are not likely to store chlorine. However, laboratory studies show that repeat exposure to chlorine in air can affect the immune system, the blood, the heart, and the respiratory system of animals.

French chemist Claude Louis Berthollet, noting the bleaching properties of chlorine, invented hypochlorite bleach in 1789.

Hope this helps

Answer 2

There are two basic kinds of bleach, oxidizing and reducing.
Household bleach is a water solution of sodium hypochlorite (NaOCl) and is in the oxidizing category.

Hair bleach is hydrogen peroxide, H2O2 and is in the reducing category.

Dyes and pigments (those chemicals that make things have a color) contain moleculesl called chromophores. The oxidizing bleaches (like household bleach) break the chemical bonds in the chromophores and create new compounds which do not have color.

The reducing bleaches, like hydrogen peroxide, change double bonds to single bonds, again producing new compounds which do not have color.

Sodium hypochlorite was invented in 1789 by a French chemist, Berthollet, so "old timey" people did have it.

Because the bleach is so corrosive it causes much harm to pipes in waste-water treatment plants so it has to be carefully moniotored and the pipes inspected and replaced often. It can kill bacteria because its by-products when it breaks down in water can diffuse into the cells of bacteria and kill the cells.

The "chlorine" used in swimming pools is actually sodium hypochlorite also. Chlorine is a very poisonous gas and would not be safe to use.

Answer 3

Bleach is Sodium Chlorate (I) NaClO........it's a Oxidising agent. In science it turns dyes colourless which explains why it is very effective for domestic purposes....esp.washing whites.