Science, Tech, Math › Science List of the Strong Acids and Key Facts Share Flipboard Email Print Laguna Designs / Getty Images Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Anne Marie Helmenstine, Ph.D. Facebook Twitter Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. Learn about our Editorial Process Updated on September 01, 2021 In chemistry, there are seven "strong" acids. What makes them "strong" is the fact that they completely dissociate into their ions (H+ and an anion) when they are mixed with water. Every other acid is a weak acid. Because there are only seven common strong acids, it is easy to commit the list to memory. Key Takeaways: List of the Strong Acids A strong acid is one which completely dissociates in its solvent. Under most definitions, the acid dissociates into a positively-charged hydrogen ion (proton) and a negatively-charged anion.The seven most common strong acids are hydrochloric acid, nitric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, perchloric acid, and chloric acid. Most other acids people encounter are weak acids.A strong acid has a pKa value less than -2. List of the Strong Acids Note that some chemistry instructors may refer only to six strong acids. That typically means the first six acids on this list: HCl: Hydrochloric acid HNO3: Nitric acid H2SO4: Sulfuric acid HBr: Hydrobromic acid HI: Hydroiodic acid (also known as hydriodic acid) HClO4: Perchloric acid HClO3: Chloric acid Other Strong Acids There are other strong acids, but they aren't encountered in everyday situations. Examples include triflic acid (H[CF3SO3]) and fluoroantimonic acid (H[SbF6]). Are Strong Acids Always Strong? As the strong acids become more concentrated, they may be unable to fully dissociate. The rule of thumb is that a strong acid is 100 percent dissociated in solutions of 1.0 M or lower concentration. Dissociation and pKa Values The general form of the dissociation reaction of a strong acid is as follows: HA + S ↔ SH+ + A- Here, S is a solvent molecule, such as water or dimethyl sulfoxide (DMSO). For example, here is the dissociation of hydrochloric acid in water: HCl(aq) → H+(aq) + Cl-(aq) A strong acid has a pKa value less than -2. The pKa value of the acid depends on the solvent. For example, hydrochloric acid has a pKa value of about -5.9 in water and -2.0 in DMSO, while hydrobromic acid has a pKa value around -8.8 in water and about -6.8 in DMSO. A Closer Look at Some of the Strong Acids Hydrochloric acid: Hydrochloric acid also goes by the name of muriatic acid. The acid is colorless and has a pungent odor. Humans and most other animals secrete hydrochloric acid in the digestive system. The acid has many commercial applications. It is used to produce inorganic compounds, refine metals, pickle steel, and regulate pH. Of the common strong acids, it is one of the least hazardous to handle, least expensive, and easiest to store.Nitric acid: Nitric acid also goes by the name aqua fortis. It is a highly corrosive acid. While colorless in pure form, nitric acid yellows over time as it decomposes into nitrogen oxides and water. In chemistry, one of its key uses is for nitration. This is where a nitro group gets added to a molecule (usually organic). Nitric acids finds use as an oxidant in nylon production, as the oxidizer in rocket fuel, and as an analytical reagent.Sulfuric acid: Sulfuric acid (American spelling) or sulphuric acid (Commonwealth spelling) is also called oil of vitriol. It is colorless, odorless, and viscous. Pure sulfuric acid does not naturally exist because the acid so strongly attracts water vapor. It's a dangerous acid to handle because it is highly corrosive and powerfully dehydrates skin upon contact, causing both acid chemical burns and thermal burns. It's primary use is in the production of fertilizers. It is also used to make detergents, dyes, resins, insecticides, paper, explosives, acetate, batteries, and drugs. Sulfuric acid is also used in water treatment. Sources Bell, R. P. (1973). The Proton in Chemistry (2nd ed.). Ithaca, NY: Cornell University Press.Guthrie, J.P. (1978). "Hydrolysis of esters of oxy acids: pKa values for strong acids". Can. J. Chem. 56 (17): 2342–2354. doi:10.1139/v78-385Housecroft, C. E.; Sharpe, A. G. (2004). Inorganic Chemistry (2nd ed.). Prentice Hall. ISBN 978-0-13-039913-7.Miessler G.L.; Tarr D.A. (1998). Inorganic Chemistry (2nd ed.). Prentice-Hall . ISBN 0-13-841891-8.Petrucci, R. H.; Harwood, R. S.; Herring, F. G. (2002). General Chemistry: Principles and Modern Applications (8th ed.). Prentice Hall. ISBN 0-13-014329-4. Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "List of the Strong Acids and Key Facts." ThoughtCo, Sep. 2, 2021, thoughtco.com/list-of-the-strong-acids-603651. Helmenstine, Anne Marie, Ph.D. (2021, September 2). List of the Strong Acids and Key Facts. Retrieved from https://www.thoughtco.com/list-of-the-strong-acids-603651 Helmenstine, Anne Marie, Ph.D. "List of the Strong Acids and Key Facts." 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