There are 118 elements in the world, and the combination of atoms of various elements can form thousands of substances of different properties, some of which are highly corrosive.
Decay is a biological phenomenon caused by the reproduction of microorganisms. Corrosion is different from decay, corrosion is a chemical phenomenon, very common in daily life, when a solid and another substance in contact, can be chemically damaged by the substance, it means that the substance is corrosive.
Corrosion is divided into many cases, such as iron rust is corroded by oxygen, this corrosion belongs to oxidation; and sulfuric acid can be removed from the hydrogen atoms and oxygen atoms in the corroded object in a 2:1 ratio, because the ratio of hydrogen and oxygen in the water molecule is also 2:1, so the corrosiveness of sulfuric acid is also called dehydration; sodium hydroxide will destroy the protein of the corroded object, resulting in a corrosive effect.
In nature, there are many corrosive substances, and the corrosion intensity is also different. Most of these highly corrosive substances belong to strong acids and strong bases. In addition, some strong oxidants, dehydrating agents, etc. also have strong corrosiveness. Even metals with weak chemical activity will be corroded when they encounter these super corrosive substances.
What are acids and bases < h1 class="pgc-h-arrow-right" >? </h1>
Acids and bases are collective terms for a class of compounds, respectively. And human understanding of acids and bases has gone through a long time. Originally, people called sour substances acid, and astringent substances called alkali. It was not until the 17th century that the British chemist Boyle gave a more scientific definition of the distinction between acid and base.
According to the theory of acid-base ionization, acids are all H+ compounds that are ionized in aqueous solutions, and alkalis are all OH- compounds that are ionized in aqueous solutions. The essence of the acid-base reaction is the reaction of H+ combined with OH- to form water. According to this theory, the pH, that is, the pH, can be determined by the concentration of H+ in the solution. The smaller the pH, the more acidic the solution; the greater the pH, the more alkaline the solution. The theory was proposed by the Swedish scientist Alenius in 1887. However, the theory has a limitation, that is, the acid-base concept cannot exist independently of water solvents.
In 1905, Franklin proposed the theory of acid-base solvents, further developed the theory of acid-base ionization, and introduced non-aqueous solvents. The theory is that the solute that produces the characteristic cation of the solvent in the solvent is called acid, and the solute that produces the characteristic anion of the solvent is called alkali. The theory is still flawed, that is, the acid-base concept cannot exist independently of solvents.
In acid-base proton theory, acid is the giver of protons (H+), while alkali is the recipient of protons (H+). The theory was proposed independently in 1923 by the Danish chemist Bronster and the British chemist Thomas Martin Laurie. According to the theory, acid and base are relative, for example, nitric acid is an acid in water, and when dissolved in pure sulfuric acid, it is an alkali.
Shortly after the acid-base proton theory was proposed, in 1923, the American chemist Gilbert Lewis proposed a broader theory of acid-base electrons, and all substances that can accept electron pairs are called acids, and all substances that can give electron pairs are called alkalis. The theory is a very broad acid-base theory.
It must be noted here that the greater the acidic or alkaline strength, the more corrosive it is. For example, hydrofluoric acid, although it has strong corrosiveness, can strongly corrode metals, glass and other substances, but it is a weak acid.
<h1 class="pgc-h-arrow-right" > the most corrosive acid in the world</h1>
According to the size of the pH, acids can be divided into strong acids and weak acids, common strong acids are perchloric acid, hydroiodic acid, sulfuric acid, hydrobromic acid, hydrochloric acid, nitric acid, iodic acid, etc., of which perchloric acid (HClO4) is the most acidic acid in inorganic oxygen-containing acid.
However, the above are not the most acidic substances, the most corrosive acid known in the world is fluoroantimony acid (HSbF6), which is made of hydrofluoric acid and antimony pentafluoride in a 1:1 ratio, and the acidic strength is 2×10^19 times stronger than the strength of pure sulfuric acid. Its corrosiveness is also very scary, usually only in containers made of tetrafluoroethylene (Teflon), and other things will be corroded by it.
Acidic second only to fluoroantimic acid is fluoroantimonysulfonic acid, also known as magic acid (SbF5 · HSO3F）。 It is a mixed acid mixed by antimony pentafluoride, a Lewisic acid, and a fluorosulfonic acid, a protonate, in a volume ratio of 1:1, which is a colorless and transparent viscous liquid with an acidity of 10 trillion times that of pure sulfuric acid. Abrasive acid is also very corrosive, much more corrosive than aqua regia.
For super-strong acids with an acidity exceeding pure sulfuric acid (H2SO4), the traditional pH value has no way to describe its acidity, and it needs to be expressed by the Hamite acidity function (H0).
In the indicator:
H0 of fluoroantimic acid [1:1] = -28,
H0 of magic acid or fluoroantimonysulfonic acid [1:1] = -25,
H0 value of carbon boraneic acid = -18.0,
H0 value of fluorosulfonic acid = -15.6,
H0 value of trifluoromethanesulfonic acid = -14.6,
H0 value of perchloric acid = -13,
H0 value of pure sulfuric acid = -11.93.
Most strong acids are highly corrosive, but there are exceptions. For example, the carboboranic acid (CHB11Cl11) in super acids is the most acidic monoacid known, and its acidity is a thousand times that of fluorosulfonic acid and 1 million times that of pure sulfuric acid, but it is almost non-corrosive. Hydrofluoric acid (HF) in weak acids is highly corrosive. Aqua rebas (HNO3·3HCl) is also a very corrosive mixture, also known as pauric acid, nitro hydrochloric acid, is a very corrosive, yellow mist liquid, by concentrated hydrochloric acid and concentrated nitric acid according to the volume ratio of 3:1 mixture, is one of the few liquids that can dissolve gold, but its acidity is weaker than concentrated sulfuric acid.
Common strong bases are lithium hydroxide, sodium hydroxide, potassium hydroxide, etc., similar to acids, most strong bases also have strong corrosiveness. However, there is a difference in the substances that can be corroded by strong acids and strong alkalis. Alkaline than sodium hydroxide (NaOH) is generally called super base, such as sodium amino, butyl lithium and so on. As for which of the bases is the most corrosive, this is inconclusive.
In fact, corrosiveness is a very complex problem, which is related to many factors. Some substances are resistant to acids but not alkalis, some substances are alkali resistant to acids, and it is difficult to compare who is more corrosive with strong acids and strong bases. However, in general, strong acids can corrode more substances in daily life. Then the most corrosive substance known in the world should be fluoroantimonic acid.