What Is Sodium Hydroxide?
Sodium hydroxide (NaOH), an odorless, white monoclinic crystal, is a potent alkaline material in various industrial processes. Due to its classification as a deleterious substance under regulatory laws, handling it requires strict safety measures.
Uses of Sodium Hydroxide
Applications of sodium hydroxide span diverse sectors:
1. Detergents
It’s crucial in soap making for its saponifying effect and is used in kitchen detergents for oil removal.
2. Paper and Textile Industry
NaOH treats wood and plant fibers for pulp production and paper smoothing. It also processes cotton and hemp for enhanced flexibility and luster in textiles.
3. Industrial Applications
As a raw material, it facilitates ester hydrolysis, alkaline oxidation, and aromatic compound hydroxylation. It’s also employed in the electronics sector for silicon wafer etching and surface modification.
Additionally, NaOH finds use in food additives, dye production, agricultural chemicals, pharmaceuticals, as an analytical reagent, desiccant, and carbon dioxide absorbent.
Properties of Sodium Hydroxide
Sodium hydroxide, or caustic soda, is highly soluble in water, generating significant heat upon dissolution. It’s deliquescent, absorbing atmospheric moisture, and dissolves in ethanol and glycerin but not in ether or acetone. Its strong alkalinity can dissolve skin proteins upon contact, emphasizing the need for careful handling and storage in dry, airtight containers.
Other Information on Sodium Hydroxide
How Sodium Hydroxide Is Produced
Sodium hydroxide is industrially produced by electrolysis of brine. Other production methods are also described below.
1. Electrolysis of Brine
Brine electrolysis is the most common method of sodium hydroxide production using electrolysis and ion exchange membranes. In this method, brine (NaCl) is electrolyzed to produce sodium hydroxide (NaOH) and chlorine (Cl2).
2. Treatment of Salt With Calcium Hydroxide
Ca(OH)2 + 2NaCl → 2NaOH + CaCl2
In this method, sodium hydroxide is produced by the reaction of calcium hydroxide and sodium chloride.
3. Ammonia Treatment of Sodium Hydroxide
2NH3 + 2NaCl + H2O → 2NaOH + 2NH4Cl
In this method, ammonia (NH3) reacts with brine (NaC) to produce sodium hydroxide.
4. Complex Decomposition Reaction of Calcium Hydroxide (Slaked Lime) and Sodium Carbonate
Ca(OH)2 + Na2CO3 → 2NaOH + CaCO3
Sodium hydroxide can also be obtained by mixing a solution of calcium hydroxide and sodium carbonate.
Each production method may require subsequent refining for purity.