There are hundreds of examples of acids and bases that can be found in all branches of chemistry, but that as a whole are separated into two large families: inorganic and organic. Inorganic acids are usually known as mineral acids, characterized by being especially strong compared to organic ones.
Acids and bases are understood as substances that have sour or saponaceous flavors, respectively. Both are corrosive, although the word 'caustic' is often used for strong bases. In short: they burn and corrode the skin if they touch it. Its characteristics in solvent media have guided a series of definitions throughout history.
Behavior of acids and bases when dissolved in water. Source: Gabriel Bolívar.
The image below shows the generic behavior of acids and bases when they are added or dissolved in a glass of water. Acids produce solutions with pH values below 7 due to hydronium ions, H 3 O +; while the bases produce solutions with a pH above 7 due to the hydroxyl (or hydroxyl) ions, OH -.
If we add hydrochloric acid, HCl (red drop), to the glass, there will be H 3 O + and Cl - ions hydrated. On the other hand, if we repeat the experiment with sodium hydroxide, NaOH (purple drop), we will have OH - and Na + ions.
Definitions
The increasingly studied and understood characteristics of acids and bases established more than one definition for these chemical compounds. Among these definitions we have that of Arrhenius, that of Bronsted-Lowry, and finally that of Lewis. Before citing the examples it is necessary to be clear about this.
Arrhenius
Acids and bases, according to Arrhenius, are those that, when dissolved in water, produce H 3 O + or OH - ions, respectively. That is, the image already represents this definition. However, by itself it neglects some acids or bases too weak to produce such ions. This is where the Bronsted-Lowry definition comes in.
Bronsted-Lowry
Bronsted-Lowry acids are those that can donate H + ions, and bases are those that accept these H +. If an acid very easily donates its H +, it means that it is a strong acid. The same happens with the bases, but accepting H +.
Thus, we have strong or weak acids and bases, and their forces are measured in different solvents; especially in water, from which the known pH units are established (0 to 14).
Therefore, a strong acid HA will completely donate its H + to water in a reaction like:
HA + H 2 O => A - + H 3 O +
Where A - is the conjugate base of HA. Hence, the H 3 O + present in the glass with acidic solution comes from here.
Meanwhile, a weak base B will deprotonate the water to gain its respective H +:
B + H 2 O <=> HB + OH -
Where HB is the conjugated acid of B. This is the case of ammonia, NH 3:
NH 3 + H 2 O <=> NH 4 + + OH -
A very strong base can directly donate OH ions - without the need to react with water; just like NaOH.
Lewis
Finally, Lewis acids are those that gain or accept electrons, and Lewis bases are those that donate or lose electrons.
For example, the Bronsted-Lowry base NH 3 is also a Lewis base, since the nitrogen atom accepts an H + by donating its pair of free electrons (H 3 N: H +) to it. That is why the three definitions do not disagree with each other, but rather intertwine and help study acidity and basicity in a broader spectrum of chemical compounds.
Examples of acids
Having clarified the definitions, a series of acids with their respective formulas and names will be mentioned below:
-HF: hydrofluoric acid
-HBr: hydrobromic acid
-HI: hydroiodic acid
-H 2 S: hydrogen sulfide
-H 2 Se: selenhydric acid
-H 2 Te: tellurhydric acid
These are binary acids, also called hydracids, to which the aforementioned hydrochloric acid, HCl, belongs.
-HNO 3: nitric acid
-HNO 2: nitrous acid
-HNO: hyponitrous acid
-H 2 CO 3: carbonic acid
-H 2 CO 2: carbonaceous acid, which is actually better known by the name of formic acid, HCOOH, the simplest organic acid of all
-H 3 PO 4: phosphoric acid
-H 3 PO 3 or H 2: phosphorous acid, with an HP bond
-H 3 PO 2 or H: hypophosphorous acid, with two HP bonds
-H 2 SO 4: sulfuric acid
-H 2 SO 3: sulfurous acid
-H 2 S 2 O 7: disulfuric acid
-HIO 4: periodic acid
-HIO 3: iodic acid
-HIO 2: iodine acid
-HIO: hypoiodine acid
-H 2 CrO 4: chromic acid
-HMnO 4: manganic acid
-CH 3 COOH: acetic acid (vinegar)
-CH 3 SO 3 H: methanesulfonic acid
All of these acids, except formic and the last two, are known as oxacids or ternary acids.
Others:
-AlCl 3: aluminum chloride
-FeCl 3: ferric chloride
-BF 3: boron trifluoride
-Metal cations dissolved in water
-Carbocations
-H (CHB 11 Cl 11): superacid carborane
- FSO 3 H: fluorosulfonic acid
- HSbF 6: fluoroantimonic acid
- FSO 3 H SbF 5: magic acid
The last four examples make up the terrifying super acids; compounds capable of disintegrating almost any material just by touching it. AlCl 3 is an example of Lewis acid, since the metal center of aluminum is capable of accepting electrons due to its electronic deficiency (it does not complete its valence octet).
Examples of bases
Among the inorganic bases we have metal hydroxides, such as sodium hydroxide, and some molecular hydrides, such as ammonia already mentioned. Here are other examples of bases:
-KOH: potassium hydroxide
-LiOH: lithium hydroxide
-RbOH: rubidium hydroxide
-CsOH: cesium hydroxide
-FrOH: francium hydroxide
-Be (OH) 2: beryllium hydroxide
-Mg (OH) 2: magnesium hydroxide
-Ca (OH) 2: calcium hydroxide
-Sr (OH) 2: strontium hydroxide
-Ba (OH) 2: barium hydroxide
-Ra (OH) 2: radio hydroxide
-Fe (OH) 2: ferrous hydroxide
-Fe (OH) 3: ferric hydroxide
-Al (OH) 3: aluminum hydroxide
-Pb (OH) 4: lead hydroxide
-Zn (OH) 2: zinc hydroxide
-Cd (OH) 2: cadmium hydroxide
-Cu (OH) 2: cupric hydroxide
-Ti (OH) 4: titanic hydroxide
-PH 3: phosphine
-AsH 3: arsine
-NaNH 2: sodium amide
- C 5 H 5 N: pyridine
- (CH 3) N: trimethylamine
- C 6 H 5 NH 2: phenylamine or aniline
-NaH: sodium hydride
-KH: potassium hydride
-Carbaniones
-Li 3 N: lithium nitride
-Alkoxides
- 2 NLi: lithium diisopropylamide
-Diethynylbenzene anion: C 6 H 4 C 4 2- (the strongest base known so far)
References
- Whitten, Davis, Peck & Stanley. (2008). Chemistry (8th ed.). CENGAGE Learning.
- Shiver & Atkins. (2008). Inorganic chemistry. (Fourth edition). Mc Graw Hill.
- Naomi Hennah. (October 10, 2018). How to teach acids, bases and salts. Recovered from: edu.rsc.org
- Helmenstine, Anne Marie, Ph.D. (August 31, 2019). Formulas of Common Acids and Bases. Recovered from: thoughtco.com
- David Wood. (2019). Comparing Common Acids & Bases. Study. Recovered from: study.com
- Ross Pomeroy. (2013, August 23). The World's Strongest Acids: Like Fire and Ice. Recovered from: realclearscience.com
- Wikipedia. (2019). Diethynylbenzene dianion. Recovered from: en.wikipedia.org