What is Sodium Hypochlorite (Bleach)?

Sodium Hypochlorite is a greenish-yellow liquid commonly referred to as "Bleach." The chemical formula for Sodium Hypochlorite is NaOCl.

Sodium Hypochlorite is prepared by reacting dilute caustic soda solution with liquid or gaseous chlorine, accompanied by cooling.

Properties of Sodium Hypochlorite

Raw Materials: Chlorine, Sodium Hydroxide (Caustic)
Appearance: Greenish-yellow liquid
Specific Gravity: Sodium hypochlorite produced by a continuous process will have approximately 0.2% by weight excess sodium hydroxide, resulting in a specific gravity of 1.160 at 120 gpl
Stability/Decomposition: The presence of transition metal ions (copper and nickel) is known to catalyze the decomposition of liquid sodium hypochlorite, contributing to the loss of bleach strength and the formation of oxygen. Loss of sodium hypochlorite strength means more product will be needed when the bleach is used as a disinfectant.

Common Uses for Sodium Hypochorite

Sodium Hypochlorite is the main ingredient in laundry bleach. It is used extensively as a bleaching agent in the textile, detergents, and paper and pulp industries. It is also used as an oxidizing agent for organic products. In the petrochemical industry, sodium hypochlorite is used in petroleum products refining. Large quantities are also used as a disinfectant in water and wastewater treatment and sanitary equipment. In food processing, sodium hypochlorite is used to sanitize food preparation equipment, in fruit and vegetable processing, mushroom production, hog, beef and poultry production, maple syrup production, and fish processing.

In various parts of the world, sodium hypochlorite strength is identified using five common definitions that result in different numbers although the oxidizing power is the same, i.e., the sodium hypochlorite strength is the same.

Sodium Hypochlorite Terms to Define Bleach Strength

Sodium Hypochlorite is used in varying strengths. The chart below lists some of the varying strengths of Sodium Hypochlorite and how the variations are typically used.

*Note: The higher the Weight Percent of Sodium Hypochlorite, the more decomposition of sodium hypochlorite becomes a factor. See Decomposition of Sodium Hypochlorite for more information.

Sodium Hypochlorite
Wt. % Common Uses
2% Shock Chlorination of Wells
3-6% Household Disinfectant, Laundering Clothes, Dentistry Root Canal Treatment, Antisepsis of Mammary Glands in Dairy Industry, Disinfectant in Hospitals, Food Processing, Mushroom Production, Hog, Beef, and Poultry Productions, Maple Syrup Production, Fish Processing, etc.
12-16% Disinfectant in Swimming Pools, Water Treatment, Waste Water Treatment

Sodium Hypochlorite Hazards/Precautions

Never mix Sodium Hypochlorite and Ammonia. Doing so forms a dangerous gas potentially leading to choking and breathing difficulty.

Avoid swallowing and getting sodium hypochlorite in the eyes or on the skin. Depending on the strength of sodium hypochlorite, severity can range from mild irritation to severe burns.

In the event sodium hypochlorite is swallowed, seek emergency help immediately. If the affected person is alert, give them milk or water to drink. Do not induce vomiting. Seek immediate medical attention.

Skin or eyes should be immediatley flushed continuously and thoroughly if coming into contact with sodium hypochlorite. Seek immediate medical attention.

In the event of inhalation of sodium hypochlorite, leave the affected area and seek fresh air. If breathing is difficult, administer oxygen and seek immediate medical attention.

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