Sodium Carbonate (Na2CO3, Soda Ash, Washing Soda)

Sodium carbonate (also known as washing soda or soda ash), is a household chemical with a variety of different uses. Its chemical formula, Na2CO3, is similar to that of baking soda, NaHCO3. But baking soda is a nontoxic chemical commonly used in food preparation, while sodium carbonate is toxic. Sodium carbonate is a sodium salt obtained from carbonic acid and is found in the form of a white, odorless powder that absorbs moisture from the air, has an alkaline taste, and forms a strongly alkaline water solution. It is one of the most basic industrial chemicals. It is mostly found in a crystalline form as a heptahydrate (where its molecule contains seven molecules of water). When it dissolves in water, it is broken down to release ions of sodium and carbonate. On exposure to air, it loses the water molecules to form a monohydrate.

Because seaweed ashes were an early source of sodium carbonate, it is often called soda ash or, simply, soda. The Solvay process provides most sodium carbonate for industrial use. It is found in large natural deposits and is mined in Wyoming; it is also recovered (with other chemicals) from lake brines in California. The principal uses of sodium carbonate are in the manufacture of glass and the production of chemicals. It is also used in processing wood pulp to make paper, in making soaps and detergents, in refining aluminum, in water softening, and in many other applications. The Leblanc process, the first successful commercial process for making soda, is no longer used in the United States but played a major role in the Industrial Revolution.

While it is possible to use very small amounts of sodium carbonate in food---actually, this is done in some cases in which base is a desirable addition to food---in large amounts, sodium carbonate is toxic. Symptoms of poisoning with sodium carbonate can be quite severe, and may include diarrhea, vomiting, and difficulty swallowing. Because the compound is so caustic, health care providers warns not to induce vomiting but instead to seek prompt medical treatment.

Sodium Carbonate Sources

The most common household sources of sodium carbonate are detergents and cleaners. Many laundry soaps and dishwasher detergents include sodium carbonate as an ingredient. Some bleaches also include the chemical, although more commonly bleach is chlorine-based. Since the products in which sodium carbonate is an ingredient generally include many toxic components, it's sometimes difficult to separate the effects of sodium carbonate from the effects of other molecules, but suffice it to say, sodium carbonate-containing cleaners should be considered poisons. Other sources include some bubble bath solutions, steam iron cleaners, pulp and paper products, and clinitest tablets.

Sodium Carbonate Uses and Benefits

Industrial Uses of Sodium Carbonate

Sodium carbonate has a significant role in the glass industry where it is used as an ingredient for manufacturing glass. Firstly, a mixture of sodium carbonate, sand or silicon dioxide and calcium carbonate are heated at a very high temperature and then it is cooled down very quickly, which results in the formation of glass. It's used in flat glass for building construction as well as automobile manufacturing, both deemed important domestic economy sectors, according to the U.S. Geological Survey. That's why sodium carbonate production data is included in the Federal Reserve Board's monthly economic indicators for industrial production. About 49 percent of the soda ash from the United States is used to make glass. Companies worldwide use soda ash from the United States to make their glass. For example, Australia's major glass bottle manufacturer, ACI Glass, gets some of its soda ash from General Chemical Soda Ash of Wyoming. ACI supplies 96 percent of Australia's glass bottles for Melbourne and Adelaide. About 46 percent of U.S. soda ash is exported, according to the U.S. Geological Survey.

In brick industry, sodium carbonate is used in the form of a wetting agent. It helps in the reduction of water content in the clay and makes the task of molding the clay in the shape of a brick easier. In the dyeing industry, sodium carbonate is used to facilitate the chemical bonding between the dye and the fiber.

The second largest use for sodium carbonate is making a variety of chemicals. For example, some bleaches contain soda ash. Some 30 percent of U.S. soda ash is used to create chemicals, according to U.S. Geological Survey.

Sodium carbonate is also used to create soaps and detergents. These include automatic dishwashing soaps, some bubble bath solutions and some steam iron cleaners. About 8 percent of the soda ash from the United States is used for soaps and detergents, according to the U.S. Geological Survey.

Additionally, soda ash is used for a variety of other industrial purposes. These include paper and paper pulp production, removal of sulfur from smokestack emissions, and water treatment. Paper pulp production accounts for about 1 percent of U.S. soda ash use, while water treatment and sulfur removal account for 2 percent each, according to the U.S. Geological Survey.

Sodium carbonate is also used in oil refining and making synthetic rubber. "Other" uses make up about 3 percent of the use of U.S. soda ash, according to the U.S. Geological Survey.

Uses of Sodium Carbonate in Chemical Laboratory

Sodium carbonate is a good electrolyte and is used in the electrolysis process (chemical reaction carried out with the help of electric current). The advantage of using soda ash as an electrolyte is that it is a good conductor of electricity, and also it does not cause any kind of corrosion to the anodes used in electrolysis process. Due to its high stability, this chemical compound is often used in the quantitative analysis of acid-based solutions.

Domestic Uses of Sodium Carbonate

Washing soda is used in homes for the purpose of softening hard water. We have seen that when soaps or detergents are added to hard water, no lather is formed, which in turn adversely affects the cleaning ability of the soap. This happens because the calcium and magnesium ions present in the hard water react with soaps and detergents and changes their properties and prevents formation of lather. As a result, more detergent is required to make lather. When sodium carbonate is added to the hard water, it prevents the ions of the hard water from formation of chemical bonds and thus enables the detergent to clean dirt from the clothes easily. It is also used as a cleansing agent for the purpose of removing dirt from the surface of silver items. It is dissolved in water and the solution is used as a fungicide to kill molds in the damp areas of the house. Sodium carbonate is used as a food additive in the preparation of sherbet.

Other Uses of Sodium Carbonate

Sodium carbonate is important in taxidermy for preparing hunting trophies. When added to boiling water, it helps in the removal of flesh from the skulls and bones of dead animals. The hunting trophies thus made, provide a lot of information for biological and historical studies. Sodium carbonate acts as a strong base, so it is very commonly used to neutralize acidic effects. During the process of developing photographic films, the pH value needs to be controlled to obtain a stable alkaline condition. Therefore, sodium carbonate is very commonly used in this process to regulate the pH value. Water in the swimming pools turns acidic due to repeated addition of chlorine as a disinfectant. Sodium carbonate is added to this water to make it chemically neutral.

Sodium carbonate has so many diverse uses mainly because it is a chemically stable compound and possesses strong alkaline properties.

Sodium Carbonate Side Effects and Symptoms

Sodium carbonate is a chemical present in a variety of commonly used industrial and household products, such as certain bleaching agents, automatic dishwashing detergents and glass and paper products. This substance, also referred to as soda ash or washing soda, may cause severe side effects if swallowed, inhaled or exposed to the skin. If you develop symptoms of sodium carbonate poisoning, seek emergency medical care.

Symptoms may include:

  • Breathing problems due to throat swelling

  • Collapse

  • Diarrhea

  • Drooling

  • Eye irritation, redness, and pain

  • Hoarseness

  • Low blood pressure (may develop rapidly)

  • Severe pain in the mouth, throat, chest, or abdominal area

  • Shock

  • Skin irritation

  • Swallowing difficulty

  • Vomiting

Difficulty Breathing

Inhaling air-borne sodium carbonate may cause severe respiratory side effects, such as difficulty breathing or shortness of breath. This toxic substance may inflame your throat or respiratory tract and may cause difficulty swallowing, hoarseness or wheezing. Without appropriate medical intervention, breathing difficulties may cause life-threatening medical complications.

Stomach Upset

Accidentally swallowing sodium carbonate may cause significant irritation along your digestive tract or stomach. You may feel nauseous or begin vomiting. Diarrhea may also occur and may result in frequent, loose bowel movements. Severe or persistent nausea, vomiting or diarrhea should be discussed with your doctor as soon as possible to ensure you receive appropriate treatment and care.

Skin or Eye Irritation

Skin or eye irritation may occur if these body regions are exposed to sodium carbonate. Your skin or eyes may appear unusually red or inflamed and may begin to itch profusely. Eye irritation may also occur in conjunction with mild to moderate eye pain.

Oral, Chest or Abdominal Pain

This toxic chemical may cause side effects of mild to severe oral, chest or abdominal pain. If you develop sudden or severe pain in any of these body regions, contact a medical professional as soon as possible. Such side effects may also be signs of alternate medical problems, such as a heart attack or appendicitis.


Excessive consumption or exposure to sodium carbonate may cause shock. Shock occurs due to severely low blood pressure and may be life-threatening. Symptoms of shock include dizziness, bluish skin, confusion, weak pulse, shallow breathing, anxiety, chest pain or loss of consciousness. Emergency medical care is required if you experience symptoms of shock.
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