Carboxylic Acid – Definition, Compounds & More

A carboxylic acid is an organic compound that contains a carboxyl group (C(=O)OH). The general formula of a carboxylic acid is R–COOH, with R referring to the rest of the molecule. Carboxylic acids occur widely. Important examples include amino acids and acetic acid. Deprotonation of a carboxyl group gives a carboxylate anion. Carboxylic acids are a homologous series in which the compounds contain a functional group called the carboxyl group (-COOH).  The general molecular formula for carboxylic acids is CnH2n+1COOH. Carboxylic acids contain at least one carboxyl group. Carboxylic acids with two or more carboxyl groups attached are called dicarboxylic acids, tricarboxylic acids, etc.

Carboxylic acids are derivatives of hydrocarbons in which one or more of the hydrogen atoms in the hydrocarbon have been replaced by a carboxyl group. The first four carboxylic acids derived from alkanes are methanoic acid (HCOOH), ethanoic acid (CH3COOH), propanoic acid (C2H5COOH) and butanoic acid (C3H7COOH).

Carboxylic Acid

Carboxylic acid, any of a class of organic compounds in which a carbon (C) atom is bonded to an oxygen (O) atom by a double bond and to a hydroxyl group (―OH) by a single bond. A fourth bond links the carbon atom to a hydrogen (H) atom or to some other univalent combining group. The carboxyl (COOH) group is so-named because of the carbonyl group (C=O) and a hydroxyl group.

Carboxylic acids are commonly identified by their trivial names. They often have the suffix -ic acid. IUPAC-recommended names also exist; in this system, carboxylic acids have an -oic acid suffix. For example, butyric acid (C3H7CO2H) is butanoic acid by IUPAC guidelines. For nomenclature of complex molecules containing a carboxylic acid, the carboxyl can be considered position one of the parent chain even if there are other substituents, such as 3-chloropropanoic acid. Alternately, it can be named as a “carboxy” or “carboxylic acid” substituent on another parent structure, such as 2-carboxyfuran.

Derivatives of carboxylic Acid

Derivatives of carboxylic Acid

The carboxylate anion (R–COO or RCO2) of a carboxylic acid is usually named with the suffix -ate, in keeping with the general pattern of -ic acid and -ate for a conjugate acid and its conjugate base, respectively. For example, the conjugate base of acetic acid is acetate.

Physical properties


Carboxylic acids are polar. Because they are both hydrogen-bond acceptors (the carbonyl –C=O) and hydrogen-bond donors (the hydroxyl –OH), they also participate in hydrogen bonding. Together, the hydroxyl and carbonyl group form the functional group carboxyl. Carboxylic acids usually exist as dimers in nonpolar media due to their tendency to “self-associate”. Smaller carboxylic acids (1 to 5 carbons) are soluble in water, whereas higher carboxylic acids have limited solubility due to the increasing hydrophobic nature of the alkyl chain. These longer chain acids tend to be soluble in less polar solvents such as ethers and alcohols.[3] Aqueous sodium hydroxide and carboxylic acids, even hydrophobic ones, react to yield water-soluble sodium salts. For example, empathic acid has low solubility in water (0.2 g/L), but its sodium salt is very soluble in water.

Boiling points

Carboxylic acids tend to have higher boiling points than water, because of their greater surface areas and their tendency to form stabilized dimers through hydrogen bonds. For boiling to occur, either the dimer bonds must be broken or the entire dimer arrangement must be vaporized, increasing the enthalpy of vaporization requirements significantly.

List Of Carboxylic Acids

Straight-chained, saturated carboxylic acids
Carbon atoms Common name IUPAC name Chemical formula Common location or use
1. Formic acid Methanoic acid HCOOH Insect stings

Formic acid

Formic acid

2. Acetic acid Ethanoic acid CH3COOH Vinegar

Acetic acid

Acetic acid

3. Propionic acid Propanoic acid CH3CH2COOH Preservative for stored grains

Propionic acid

Propionic acid

4. Butyric acid Butanoic acid CH3(CH2)2COOH Rancid butter

Butyric Acid

Butyric Acid

5. Valeric acid Pentanoic acid CH3(CH2)3COOH Valerian

Valeric acid

Valeric acid

All Remaining acid structures are can be derived as given above

6. Caproic acid Hexanoic acid CH3(CH2)4COOH Goat fat
7. Enanthic acid Heptanoic acid CH3(CH2)5COOH
8. Caprylic acid Octanoic acid CH3(CH2)6COOH Coconuts and breast milk
9. Pelargonic acid Nonanoic acid CH3(CH2)7COOH Pelargonium
10. Capric acid Decanoic acid CH3(CH2)8COOH
12. Lauric acid Dodecanoic acid CH3(CH2)10COOH Coconut oil and hand wash soaps.
14. Myristic acid Tetradecanoic acid CH3(CH2)12COOH Nutmeg
16. Palmitic acid Hexadecanoic acid CH3(CH2)14COOH Palm oil
18. Stearic acid Octadecanoic acid CH3(CH2)16COOH Chocolate, waxes, soaps, and oils
20. Arachidic acid Icosanoic acid CH3(CH2)18COOH Peanut oil

Carboxyl Group/Carboxyl Functional Group Definition

The carboxyl group is an organic functional group consisting of a carbon atom double-bonded to an oxygen atom and singly bonded to a hydroxyl group. Another way to view it is as a carbonyl group (C=O) that has a hydroxyl group (O-H) attached to the carbon atom. The carboxyl group is commonly written as -C(=O)OH or -COOH. Carboxyl groups ionize by releasing the hydrogen atom from the -OH group. The H+, which is a free proton, is released. Thus, carboxyl groups make good acids. When hydrogen leaves, the oxygen atom has a negative charge, which it shares with the second oxygen atom in the group, allowing the carboxyl to remain stable even when oxidized.

The carboxyl group is sometimes referred to as the carboxy group, carboxyl functional group, or carboxyl radical. Also, We Can Say The functional group of a carboxylic acid, characterized by a carbonyl group bonded to a hydroxyl group. ‘Carboxyl’ can be thought of as a contraction of carbonyl hydroxyl.

A carboxyl group is one of many functional groups that attaches to larger molecules and gives them certain properties. The carboxyl group is seen in many organic molecules known as carboxylic acids, which have a variety of functions. The carboxyl group consists of carbon, bonded to both an oxygen and a hydroxyl group. Hydroxyl groups are simply oxygen bonded to hydrogen.

Carboxyl Group

Carboxyl Group

The double-bonded oxygen is electronegative and attracts hydrogens. The hydroxyl group does the opposite, and would gladly give up hydrogen to form another bond with carbon. In this way, carboxyl groups are polar and can participate in hydrogen bonding and a variety of other important reactions. The “R” in the above diagram can be any number of carbon-containing molecules or even a single hydrogen atom. One important example of a carboxyl group is in protein synthesis. Every amino acid has both a carboxyl group and an amino group. The bond formed between these groups allows amino acids to be chained together in long sequences and is known as a peptide bond.

Carboxyl Group Example

Probably the best-known example of a molecule with a carboxyl group is a carboxylic acid. The general formula of the carboxylic acid is R-C(O)OH, where R is any number of chemical species. Carboxylic acids are found in acetic acid and the amino acids that are used to build proteins. Because the hydrogen ion detaches so readily, the molecule is most commonly found as a carboxylate anion, R-COO. The anion is named using the suffix -ate. For example, acetic acid (a carboxylic acid) becomes the acetate ion.

What Is Carboxylic Acid Used For?

Carboxylic Acid Derivatives Have Varied Applications. For Example, In Addition To Its Use As A Disinfectant, Formic Acid, The Simplest Carboxylic Acid, Is Employed In Textile Treatment And As An Acid Reducing Agent. Acetic Acid Is Extensively Used In The Production Of Cellulose Plastics And Esters.

What Is A Carboxylic Acid Give An Example?

A Carboxylic Acid Is An Organic Compound That Contains A Carboxyl Group (C(=O)Oh). Carboxylic Acids Occur Widely. Important Examples Include The Amino Acids And Acetic Acid. Deprotonation Of A Carboxyl Group Gives A Carboxylate Anion.

How Carboxylic Acids Are Formed?

The Formation Of Carboxylic Acids. As We Noted Previously, The Oxidation Of Aldehydes Or Primary Alcohols Forms Carboxylic Acids: In The Presence Of An Oxidizing Agent, Ethanol Is Oxidized To Acetaldehyde, Which Is Then Oxidized To Acetic Acid. Acetic Acid Can Be Further Oxidized To Carbon Dioxide And Water.

What Foods Contain Carboxylic Acids?

Many Carboxylic Acids Occur Naturally In Plants And Animals. Citrus Fruits Such As Oranges And Lemons Contain Citric Acid. Citric Acid Is A Large Carboxylic Acid With Three Ionizable Hydrogen Atoms. It Is Found In Citrus Fruits And Gives Them Their Sour Or Tart Flavor.

Is Vinegar A Carboxylic Acid?

The Functional Group In The Carboxylic Acids Is The Carboxyl Group, -cooh. Vinegar Is A Dilute Solution Of Ethanoic Acid.