Alkali
The term "alkali" is applied to the soluble hydroxide of the group of metals comprising sodium, potassium, lithium, rubidium, and caesium. Of these, only the first two are important for our purpose.
Sodium mostly occurs in Nature as sodium chloride (common salt). Sodium hydroxide is caustic soda, a strong alkali which needs careful handling. It has some uses to the restorer, although it is apt to cause trouble to the archaeologist.
Sodium carbonate (or bicarbonate) can be used as an antidote to acid burns and acid poisoning. Poisoning and burns from strong alkali may be treated in an emergency with vinegar (acetic acid) or lemon (citric acid). Copious dilution of either acid or alkali with water is always to be recommended where possible as a preliminary step.
For a description of the reaction between acids and alkalis, and the product thereof, see the article on Acids.
See also Soap.