Sodium hydroxide, with the CAS register number 1310-73-2, is also called as Lye and Caustic soda. The substance is white opaque crystals. It should be stored in a tightly closed container, and in a cool, dry, well-ventilated area away from incompatible substances. In addition,Sodium hydroxide should be kept away from metals, acids and moisture. Its containers must be tightly closed to prevent the conversion of NaOH to sodium carbonate by the CO₂ in air. Sodium hydroxide is insoluble in ether and other non-polar solvents. It is very soluble in water with liberation of heat. Sodium hydroxide also can dissolve in ethanol and methanol, though it exhibits lower solubility in these solvents than does potassium hydroxide. It is hygroscopic which readily absorbs water from the air, so it should be stored in an airtight container.

Properties of Sodium hydroxide: Sodium hydroxide is predominantly ionic, containing sodium cations and hydroxide anions. The hydroxide anion makes Sodium hydroxide a strong base which reacts with acids, both organic and inorganic, to form water and the corresponding salts. Heating with a mixture of methyl alcohol and trichlorobenzene during an attempted synthesis, it will led to a sudden increase in pressure and an explosion. Sodium hydroxide will readily absorb moisture from the air to give caustic semi-solids that attacks aluminum and zinc with the evolution of flammable hydrogen gas.

Catalyzes the polymerization of acetaldehyde and other polymerizable compounds these reactions can occur violently, for example, acrolein polymerizes with extreme violence when put in contact with alkaline materials such as sodium hydroxide. Hot and concentrated NaOH can cause hydroquinone to decompose exothermically at elevated temperature.

Preparation of Sodium hydroxide: Of historic interest is the Leblanc process, which produced sodium carbonate, followed by roasting to create carbon dioxide and sodium oxide, which readily absorbs water to create Sodium hydroxide. Sodium hydroxide is produced along with chlorine and hydrogen via the chloralkali process. This involves the electrolysis of an aqueous solution of sodium chloride. The Sodium hydroxide builds up at the cathode, where water is reduced to hydrogen gas and hydroxide ion. The Cl– ions are oxidized to chlorine gas at the anode.

2 Na+Cl^- + 2 H₂O + 2 e^- → H₂ + 2 Cl^- + 2 NaOH

Sodium hydroxide is industrially produced as a 50 % solution by variations of the electrolytic chloralkali process. Solid sodium hydroxide is obtained from this solution by the evaporation of water. Sodium hydroxide may be formed by the metathesis reaction between calcium hydroxide and sodium carbonate:

Ca(OH)₂ + Na₂CO₃ → CaCO₃ + 2 NaOH

Uses of  Sodium hydroxide: 56 % of Sodium hydroxide produced is used by the chemical industry, with 25 % of the same total used by the paper industry. Sodium hydroxide is the principal strong base used in the chemical industry. It is used in many industries, mostly as a strong chemical base in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents and as a drain cleaner, sodium salts and detergents, for pH regulation, and for organic synthesis. Sodium hydroxide is used in the Bayer process of aluminium production.

Food uses of Sodium hydroxide include washing or chemical peeling of fruits and vegetables, chocolate and cocoa processing, caramel coloring production, poultry scalding, soft drink processing, and thickening ice cream. Sodium hydroxide is frequently used as an industrial cleaning agent where it is often called "caustic". It is added to water, heated, and then used to clean the process equipment, storage tanks, etc. It can dissolve grease, oils, fats and protein based deposits. Sodium hydroxide is traditionally used in soap making. Sodium hydroxide is used in all sorts of scenarios where it is desirable to increase the alkalinity of a mixture, or to neutralize acids.

When you are using Sodium hydroxide please be cautious about it as the following: The substance may cause severe burns. It is also irritating to eyes and skin. In case of contact with eyes, you should rinse immediately with plenty of water and seek medical advice. And when you use it, you should wear suitable protective clothing, gloves and eye/face protection to avoid contact with skin and eyes. Moreover, in case of accident or if you feel unwell, you can seek medical advice immediately.

You can still convert the following datas into molecular structure:
(1)Canonical SMILES: [OH-].[Na+]
(2)InChI: InChI=1S/Na.H2O/h;1H2/q+1;/p-1
(3)InChIKey: HEMHJVSKTPXQMS-UHFFFAOYSA-M

The toxicity data of Sodium hydroxide is as follows: