Sodium hydroxide, commonly known as lye or caustic soda, is an inorganic compound with the formula NaOH. It is a highly caustic metallic base and alkali salt that is used in many industries. With the chemical formula NaOH, sodium hydroxide consists of sodium cations (Na+) and hydroxide anions (OH-). It is a white solid that is highly soluble in water. In aqueous solution, it dissociates almost completely into sodium and hydroxide ions.
Sodium hydroxide has a wide variety of industrial and household uses due to its versatile chemical properties. Some key facts and uses of sodium hydroxide include:
- Manufacturing: NaOH is used extensively in pulping wood to make paper. It is also used in making soaps, detergents, drain cleaners, and as a pH regulator in water treatment. It is crucial in manufacturing processes like aluminum refining, petroleum production, textiles, and more.
- Cleaning: As a strong alkali, it is very effective at breaking down oils and grease. It is commonly used for drain cleaning, oven cleaning, and removing stains from clothes, dishes, and surfaces. However, it must be handled with care due to its corrosive nature.
- pH regulator: Sodium hydroxide helps regulate the pH of water, which is crucial for water treatment plants. It neutralizes acids in water and raises pH to make it less corrosive and safer. The pH of drinking water is usually maintained between 6.5-8.5 using NaOH.
- Food industry: It is used as an acidity regulator and neutralizing agent in food processing. Small amounts of NaOH are added to foods like baked goods to adjust pH and improve texture, shelf life and flavor.
- Personal care: Sodium hydroxide is found in hair straightening treatments, hair relaxers, and some hair removal products due to its ability to break disulfide bonds in hair and skin proteins. However, it must be formulated carefully for safety.
- Laboratory reagent: In laboratories, NaOH is commonly used as a titration reagent and to adjust pH in chemical reactions. It is also used to recover metals from ores via leaching.
While sodium hydroxide has many useful applications, it is also highly corrosive and dangerous if not handled properly. Contact with skin, eyes or if swallowed can cause severe burns and permanent damage. Therefore, it is important to use NaOH cautiously with protective equipment like gloves, eye goggles and masks. Spills should be cleaned up immediately with copious amounts of water. Overall, as a versatile strong alkali, sodium hydroxide will continue playing a crucial industrial role due to its unique chemical properties and reactivity.