Caustic soda, or sodium hydroxide (NaOH), is an inorganic compound composed of sodium (Na⁺) and hydroxide (OH⁻) ions. It is classified as a strong base and exhibits highly reactive, corrosive, and hygroscopic properties.

Chemical Structure

• Chemical Formula: NaOH
• Molar Mass: 39.997 g/mol
• Ionic Nature: Strong base, completely dissociates in water
• Ions in Solution: Na⁺ and OH⁻
• Type of Bonding: Ionic

Sodium hydroxide is highly alkaline, meaning it raises the pH of aqueous solutions significantly. A 1 molar solution of NaOH can have a pH close to 14.

Physical Properties

Property	Value
Appearance	White, opaque solid (flakes or pellets)
Odor	Odorless
Melting Point	318 °C
Boiling Point	1,388 °C
Density	2.13 g/cm³ at 20°C
Solubility in Water	111 g/100 mL at 20°C (very high)
Hygroscopic	Yes – absorbs moisture and CO₂ from air

When NaOH dissolves in water, it undergoes an exothermic reaction, releasing heat. This can raise the temperature of the solution significantly, especially at high concentrations.

Reactivity and Safety

• Highly Corrosive: Especially to skin, metals, and organic materials
• Reacts with: Acids, water, carbon dioxide, and certain metals like aluminum
• Neutralization: Reacts with acids to form salts and water
• CO₂ Absorption: NaOH can absorb CO₂ from the air to form sodium carbonate (Na₂CO₃)

Crystal and Flake Forms

Caustic soda is available commercially in flake form, which offers easier handling and storage. Flakes are thin, sharp-edged, and dissolve rapidly in water, making them ideal for industrial processes that require high solubility and fast reactivity.

Iran Caustic Soda – Scientific-Grade NaOH Flakes

Iran Caustic Soda exports high-purity sodium hydroxide flakes to industries around the world. Our product meets the highest chemical standards in terms of purity, moisture content, and reactivity—ideal for laboratories, manufacturing, and specialized industries.

Summary Table

Feature	Details
Formula	NaOH
Purity	≥98% (industrial flakes)
Solubility	Highly soluble, exothermic in water
Physical Form	White flakes
pH (1% solution)	~13–14
Stability	Stable under dry, cool conditions