Chemistry of Chlorine Bleach

Chlorine bleach is a common household chemical.

As one of the most common household chemicals, chlorine bleach is an inexpensive and effective way to sanitize and disinfect non-porous surfaces as well as whiten laundry. As a chemical solution, is it caustic and most recommended uses involve a diluted bleach solution. Chlorine bleach also reacts chemically with other common cleaning products, producing toxic gases and byproducts.

Chemical Properties

Standard household bleach contains the chemical sodium hypochlorite and water. The amount of sodium hypochlorite depends on the concentration of the solution. Typically, household chlorine bleach contains 6 percent sodium hypochlorite, and the remaining volume is water.

Formation & Degradation

Chlorine bleach is formed by combining chlorine (Cl) with sodium hydroxide (NaOH), which are initially isolated from salt water with the use of electrical currents. The purified chlorine and sodium hydroxide components are then added to pure water (H2O) to form sodium hypochlorite (ClNaO).

When chlorine bleach is used, it quickly breaks down into water, sodium and hypochlorite ions and hydrochlorous acid molecules. The presence of the hypochlorite ions and hydrochlorous molecules are responsible for disrupting the cellular functioning of microorganisms.

Physical Properties

Sodium hypochlorite solutions are clear, greenish-yellow liquids. They have strong chlorine smells.

Uses

Chlorine bleach's chemical makeup makes it useful as a disinfectant, pesticide and fungicide. It has strong anti-bacterial, anti-fungal and anti-algal properties. It is used for sanitizing food-contact surfaces, disinfecting surfaces in contact with disease-causing pathogens, whitening laundry and water treatment.

Precautions

Chlorine bleach should never be mixed with ammonia, acids or other cleaning products. When bleach is mixed with ammonia, toxic fumes called chloramines are produced. Mixing bleach with acids produces chlorine gas, which then combines with water to produce hydrochloric and hypochlorous acids. Chlorine gas is irritating to the mucous membranes (eyes, throat and nose) at low levels, and can be deadly at high levels. Hydrochloric acid exposure causes burns to the skin and mucous membranes.

References

• Chlorox: Bleach and the Environment
• Washington State Department of Health: Mixing Bleach with Other Cleaning Products is Dangerous
• Environmental Protection Agency: Chlorine Bleach