What is Sodium Hydroxide? (NaOH)
Sodium hydroxide, also known as lye or caustic soda, is a solid, ionic chemical compound (Na? OH?) that functions as a base when dissolved in an aqueous solution. The purpose of a base may fall under two definitions:
- Brønsted-Lowry bases accept protons (H?)
- Lewis bases donate electrons
Sodium hydroxide is generally known for its ability to form water (H?O) in solution while also forming salts (e.g. Na?Cl?). Typically, in order for this reaction to occur, the sodium hydroxide must react with an acid, such as hydrochloric acid (HCl). This reaction is the most simple of the acid-base reactions and serves as a foundation for all the other functions of sodium hydroxide.
Aside from functioning as base, the general characteristics of solid sodium hydroxide is an odorless, white crystalline compound. Handling the solid form requires caution as it denatures proteins and may cause chemical burns to the body. When added into an aqueous or polar solutions, sodium hydroxide is extremely soluble and forms a colorless, odorless, and basic solution.
Industries and Applications of Sodium Hydroxide
- Sodium chloride
- Energy Sector
- Cure food
- Remove skin from foods for canning
- Drain cleaner
- Oven cleaner
- Paper making
- Paper recycling
- Aluminum Ore Processing
- Oxide coating
- Processing cotton fabric
- Metal Processing
- Pharmaceuticals and Medicine
- Pain relievers
- Anticoagulants to prevent blood clots
- Cholesterol Reducing medications
- Water treatment
These are some additional things you might not know about sodium hydroxide:
- Another name for sodium hydroxide is caustic soda because it means “burning” from the way it can burn the skin.
- Sodium hydroxide is an alkali which means it easily absorbs carbon dioxide and moisture from the air.
- When sodium hydroxide easily dissolves in water, it turns the water warm.
Health Rating: 3 – The chemical has met Safer Choice Criteria for its functional ingredient class, but has some hazard profile issues. In other words, a chemical with this code is not associated with a low hazard concern for environmental endpoints and human health.
The U.S. Occupational Safety & Health Administration (OSHA) has put guidelines in place for allowable exposure limits for workers in industries and facilities where sodium hydroxide substances are present.
Refer to this Safety Data Sheet for information on handling sodium hydroxide acid safely.