The Full Wiki

More info on Salt (chemistry)

Salt (chemistry): Wikis

Advertisements
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Encyclopedia

From Wikipedia, the free encyclopedia

The blue salt copper(II) sulfate in form of the mineral chalcanthite

In chemistry, salts are ionic compounds which can result from the neutralization reaction of acids. Salts are ionic compounds composed of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge). These component ions can be inorganic such as chloride (Cl), as well as organic such as acetate (CH3COO) and monoatomic ions such as fluoride (F), as well as polyatomic ions such as sulfate (SO42−).

There are several varieties of salts. Salts that produce hydroxide ions when dissolved in water are basic salts and salts that produce hydronium ions in water are acid salts. Neutral salts are those that are neither acid nor basic salts. Zwitterions contain an anionic center and a cationic center in the same molecule but are not considered to be salts. Examples include amino acids, many metabolites, peptides and proteins.

When salts are dissolved in water, they are called electrolytes, and are able to conduct electricity, a property that is shared with molten salts. Mixtures of many different ions in solution—like in the cytoplasm of cells, in blood, urine, plant saps and mineral waters—usually do not form defined salts after evaporation of the water. Therefore, their salt content is given for the respective ions.

Contents

Properties

Potassium dichromate, a bright orange salt used as a pigment
Advertisements

Color

Salts can appear to be clear and transparent (sodium chloride), opaque, and even metallic and lustrous (iron disulfide). In many cases the apparent opacity or transparency are only related to the difference in size of the individual monocrystals. Since light reflects from the grain boundaries (boundaries between crystallites), larger crystals tend to be transparent, while polycrystalline aggregates look like white powders. Of course, some salts are opaque.

Salts exist in many different colors, e.g.

Most minerals and inorganic pigments as well as many synthetic organic dyes are salts.

Taste

Different salts can elicit all five basic tastes, e.g. salty (sodium chloride), sweet (lead diacetate; which will cause lead poisoning if ingested), sour (potassium bitartrate), bitter (magnesium sulfate), and umami or savory (monosodium glutamate).

Odour

Salts of strong acids and strong bases ("strong salts") are non-volatile and odorless, while salts of either weak acids or weak bases ("weak salts") may smell after the conjugate acid (e.g. acetates like acetic acid (vinegar) and cyanides like hydrogen cyanide (almonds)) or the conjugate base (e.g. ammonium salts like ammonia) of the component ions. That slow, partial decomposition is usually accelerated by presence of water, since hydrolysis is the other half of the reversible reaction equation of formation of weak salts.

Nomenclature

Manganese dioxide, an opaque black salt
Cocaine hydrochloride, an organic salt

The name of a salt starts with the name of the cation (e.g. sodium or ammonium) followed by the name of the anion (e.g. chloride or acetate). Salts are often referred to only by the name of the cation (e.g. sodium salt or ammonium salt) or by the name of the anion (e.g. chloride or acetate).

Common salt-forming cations include:

Common salt-forming anions (parent acids in parentheses) include:

Formation

Salts are formed by a chemical reaction between:

References

  • Mark Kurlansky (2002). Salt: A World History. Walker Publishing Company. ISBN 0-14-200161-9.

See also


Advertisements






Got something to say? Make a comment.
Your name
Your email address
Message