Characteristics of Acids

Acids are chemical compounds that when reacting with other compounds or elements release hydrogen ions which react by attacking and corroding. They are commonly found in a liquid and a gaseous state, although there are some solids, such as benzoic acid.

They are divided into two large groups:

1. Mineral or inorganic acids.
2. Organic acids.

Inorganic acids are divided into hydracids and oxacids.

Hydracids are those acids that lack oxygen. In them it combines Hydrogen with a nonmetal or a metalloid. Many are gaseous and form acidic aqueous solutions, which is how they can be found on the market, such as hydrochloric acid (HCl) that is commercially available under the name of muriatic acid or hydrogen chloride, and is sold dissolved in water in solutions from 5 to 20%.

Oxacids are acids in which oxygen molecules are present, since the presence of water is necessary for the formation of the acid. An example is sulfuric acid, with the formula H2SO4, and it is the product of the reaction of sulfur dioxide with water and nitric acid.

In mineral acids, hydrogen combines with metals or metalloids; Hydracids are formed by the union of hydrogen with nonmetals and sulfur. Examples of this are Hydrogen Sulfide (H S), Hydrobromic (H Br) and Hydrochloric (H Cl) (also called muriatic). Oxacids are formed when oxygen enters its formula; They react with a non-metallic oxide or anhydride and water, including carbonic and sulfuric.

Organic acids:

Organic acids are derived from organic molecules, that is, they contain carbon skeletons, in which there is a radical called carboxyl (COOH) in which at the end of the radical there is a hydrogen atom that is released when combining or reacting in the functions biochemicals. It is produced by living organisms and is involved in many vital functions of both plants and animals. Some of these acids are acetic acid, citric acid, or salicylic acid. Depending on the amount of carboxyl radicals that a molecule contains, they can be monoacid, diacid, triacid, etc.

Some of the characteristics of Acids:

Reactivity.- Acids have a certain level of reactivity, that is, more or less facility to react with other substances. According to this criterion they are divided into weak acids and strong acids.

Weak acids are characterized by little dissociation (separating their hydrogen ions) in an aqueous solution. Most organic acids are weak acids.

Strong acids release large amounts of ions in a solution and are very reactive. Most inorganic acids are strong acids.

Electrolysis.- By dividing acids into ions, ionic hydrogen has a positive charge (cation) and the element with which they combine acquires a negative charge (anion). This dissociation allows the solution to become electrolytic, that is, it can conduct electricity.

Neutralization.- When an acid is mixed with compounds called bases or hydroxides, whose characteristic is that they contain a hydroxyl ion (OH), whose charge is positive; the components react with each other, resulting in a salt and water. When hydrochloric acid (HCl) is mixed with potassium hydroxide (KOH), both molecules dissociate, giving rise to 4 ions: Cl-, H +, K + and OH-. The result of the reaction is the salt of potassium chloride (KCl) and water (H2O).

Reaction with metals. When they come into contact with some metals such as zinc and magnesium, they release hydrogen in its gaseous form (H2).

Release of energy. By reacting with other substances, acids have an exogenous reaction, that is, they release heat.

Degree of Acidity.- Each acid has a degree of reactivity that ranges from neutral to very acidic. To measure it, the ph scale (hydrogen potential) is used. It is a logarithmic scale that is graduated from 0 to 14, with 0 being a very acidic substance (which releases a lot of hydrogen) and 14 a very alkaline substance (which releases a lot of hydroxyl). The number 7 indicates a neutral substance. Acids have a pH of less than 7. To determine some degrees of acidity, reagents such as litmus paper or some vegetable reagents are used, the which change color and present characteristic colorations depending on the acidity or alkalinity of the substance reactive.

Consistency.- Acids have different consistencies. Hydracids tend to be gaseous, and dissolve in water, while hydracids are generally originally liquid or oily in consistency. Many inorganic acids in their natural state are dissolved in water; once isolated, they have a solid crystalline consistency. The fatty organic acids that exist within living organisms have an oily consistency.

Corrosion.- Acids electrochemically attack different substances, corroding them; this is the case of sulfuric that corrodes a great variety of substances such as metals and other minerals and organic substances. For example, hydrofluoric acid corrodes and dissolves organic tissue and mucous membranes, even in its gaseous form, so you should always avoid inhaling it.

Acrimony.- Due to acidity, all acids have a pungent and sour taste, defined as sour. This sensation of acrimony is perceived through taste, mainly in organic acids, an example of this type is the Citric acid, which is found in a wide variety of foods, such as oranges, lemons, tangerines, grapefruits, pineapples, guavas or limes. Other stronger acids can be perceived through smell. However, caution must be exercised and avoided as much as possible, since many react and burn the respiratory mucous membranes.

They are part of living organisms. Some acids are involved in various ways in living organisms. From its microscopic structure (nucleic acids) to some food substances such as vitamins or nutrients produced by some vegetables, such as capsic and citric acids. Some inorganic acids are involved in other functions such as hydrochloric acid produced in the stomach.