What is lye water


Alkalis are solutions of compounds that are able to take up protons. The most common are the aqueous solutions of the alkali metal hydroxides NaOH and KOH. In addition, ammonia can act as a Brönsted base and therefore also forms a weak alkali. The hydroxides of the alkaline earth metals are only soluble in small amounts and therefore only form weak alkalis (e.g. "lime water").

1st possibility:

Alkali metal + water → alkali + hydrogen

or alkaline earth metal

2nd possibility:

Metal oxide + water → hydroxide

The solution of metal hydroxide in water is an alkali.

All bases color colorless phenolphthalein solution red and litmus blue. Alkalis have a pH value> 7 to 14.

    dissolve fats → therefore use as a cleaning agent

    attack horn-like substances (e.g. sheep's wool, natural silk, horny layer of the skin)

    taste soapy when heavily diluted

    have a corrosive effect and are very dangerous in higher concentrations

    do not attack vegetable fibers (cotton, linen, wood)

    attack metals (except zinc and aluminum) Not at

    in soap manufacturing

    in paper production

    in the production of pretzels

    as a cleaning agent

    as a paint remover

Alkalis consist of metal ions and one or more OH groups. The OH group is the characteristic component of the alkalis.

Note: Salmiakgeist (formally NH4OH):

The NH4 -Group behaves like a monovalent metal.

most important representatives

aqueous solutionformula hard materialEveryday name
Caustic soda NaOH Sodium hydroxide caustic soda
Potassium hydroxide KOH Potassium hydroxide Caustic potash
Lithium lye    Lithium hydroxide  
Ammonia solution NH4OH Ammonia
Calcium hydroxide Ca (OH)   Calcium hydroxide Lime water