Web Guide: Encyclopedia

Sodium hydroxide

Redirected from Lye

Properties

General
Name	Sodium hydroxide
Chemical formula	NaOH
Appearance	White solid
Physical
Formula weight	40.0 amu
Melting point	596 K (323 °C)
Boiling point	1663 K (1390 °C)
Density	2.1 ×103 kg/m3
Crystal structure	?
Solubility	?
Thermochemistry
ΔfH0gas	-197.76 kJ/mol
ΔfH0liquid	-416.88 kJ/mol
ΔfH0solid	-425.93 kJ/mol
S0gas, 1 bar	228.47 J/mol·K
S0liquid, 1 bar	75.91 J/mol·K
S0solid	64.46 J/mol·K
Safety
Ingestion	May cause severe and permanent damage to the GI system.
Inhalation	Irritation for low exposures, may be harmful or fatal in higher doses.
Skin	Dangerous. Symptoms range from mild irritation to nasty ulcers.
Eyes	Dangerous. May cause burns, damage to cornea or conjuctiva.
More info	Hazardous Chemical Database (http://ull.chemistry.uakron.edu/erd/chemicals/8/7069.html)
SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references

Sodium hydroxide (NaOH), also known as caustic soda or lye, is a caustic[?] hydroxide used in industry (mostly as a strong chemical base) in the manufacture of paper, textiles, and detergents.

Sodium hydroxide is occasionally used in the home as an agent for unclogging stuck drains, but it is highly corrosive and has a high danger of causing chemical burns[?], permanent injury or scarring, and blindness, due to its high reactivity[?].

When sodium hydroxide reacts with water, it can become hot enough to cause fires. For this reason, it is important to have the proper type of chemical fire extinguisher on hand before working with sodium hydroxide.

Sodium hydroxide is manufactured by electrolysis of an aqueous solution of sodium chloride. It is a by-product of the process that is used to make chlorine.

A solution of a small portion of lye diluted in water is used in the traditional method of making a pretzel.

Elsewhere

Search engine
Web directory