Caustic soda, also known as sodium hydroxide (NaOH), is a corrosive white crystalline solid.
It is strongly alkaline, meaning it readily dissolves in water and releases hydroxide ions (OH-), giving it a pH of around 14.
It is primarily produced through electrolysis. This process involves passing an electric current through a brine solution (sodium chloride dissolved in water) to separate the sodium and chloride ions.
Uses:
- Cleansing agent: Unblocking drains, drain pipe cleaner, removes built up grease from ovens.
- Soap and detergent production: Key ingredient in the production of soap and detergents.
- Chemical manufacturing: Used in the production of a variety of chemicals, including chlorine, rayon, and paper.
- Aluminium production: Used in Bayer process to extract aluminium from aluminium ore.
- Textile processing: Used in processing of textiles, such as mercerizing cotton and finishing fabrics.
- Food processing: Used in food industry as an acidity regulator and an anti-caking agent.
- Oil refining: Used to remove sulphur impurities from crude oil.
- Water treatment: Used to adjust the pH of water and remove certain contaminants.
- Biodiesel production: Used as a catalyst in the production of biodiesel. [Biodiesel is made by reacting vegetable oil or animal fat with an alcohol (methanol or ethanol) and a catalyst (sodium hydroxide or potassium hydroxide)].