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Washing Soda Ingredients

We use products with washing soda as the main substance on a daily basis. Let's see its exact contents.
Deeptee A Nov 6, 2018
Washing soda is a white powder soluble in water used in soaps and detergents amongst others. It has industrial, commercial, and domestic uses. Having sodium carbonate as the chemical name and soda ash as industrial name, the chemical structure of washing soda is Na2CO3.
It mainly occurs in a colorless and transparent crystalline form and converts into a powder when the crystal loses all the water. It decomposes when heated. There are two forms of sodium carbonate - light soda and dense soda. Let's find out some more about its ingredients.
Sodium carbonate is derived from many sources. When seasonal lakes evaporate, they leave a huge chunk of mineral deposits behind. These deposits are good sources of sodium carbonate.
Other dry lakes and wells are also good sources of the same. It is also believed to have been erupted from volcanoes. Large deposits of sodium carbonate are found in Africa and North America.
Apart from natural sources, there are other ways to manufacture sodium carbonate. Here are some of the most used and known manufacturing processes.

Solvay Process

This process involves adding of ammonia in a sodium chloride solution. Sodium bicarbonate is precipitated by bubbling carbon dioxide through the solution. This sodium bicarbonate decomposes into sodium carbonate or washing soda after it is heated.

Leblanc Process

This process involves the use of sea salt, coal, sulfuric acid, and crushed limestone. Sea salt is boiled with sulfuric acid which forms sodium sulfate. Crushed limestone and coal is later added to this sodium sulfate to form a mixture.
This mixture is burnt which produces calcium sulfide. Washing soda is extracted by adding water to these ashes and letting it evaporate. However, this process highly pollutes the air and is hence not used since the 1880s.

Hou's Process

Long story short, Hou's process is an upgradation of the Solvay process. The first few steps remaining the same, carbon dioxide and ammonia are pumped into the solution instead of limestone.
Further, sodium chloride is added and this solution is left to saturate at 40ºC. It is then cooled to 10ºC and recycled to produce sodium carbonate. Ammonium chloride also precipitates in this process.


It is primarily used domestically as a water softener and in water treatment. It is also used in the manufacture of glass and paper. Sodium carbonate (soda ash) is cheaper and safer to handle and is hence used as a common base in many industries.
Commercially, sodium carbonate is important for the manufacture of baking soda that is used in fire extinguishers. It is used to remove sulfur dioxide from fuel gases. The main reason to add washing soda as one of the important laundry detergent ingredients is because it is the cheaper alternative to lye, that is needed in making soap.

Environmental Impact

Sodium carbonate is alkaline in nature with pH level of 11.6. If it is released in water, the pH value of water as well as the level of alkalinity will increase. This might affect the aquatic life and water quality.
The environment also gets affected when washing soda is manufactured by the chemical processes. The byproducts of these processes are enough to cause air pollution which is harmful.