Carboxylic Acid Properties (23 Facts You Should Know)

A carboxylic acid is an organic compound with a carboxyl functional group (COOH). Let us discuss the various physical and chemical characteristics of carboxylic acid.

Carboxylic acids are regarded to be the derivatives of hydrocarbons, which are produced when carboxylic radicals replace one or more hydrogen atoms. They are extensively found in nature and are also synthetically produced by humans. Amino acids and fatty acids are examples of well-known carboxylic acids.

In this article, we shall discuss carboxylic acid’s bonding, acidity, melting point, and boiling point in detail.

Carboxylic Acid IUPAC Name

The carboxylic acid’s IUPAC name (International Union of Pure and Applied Chemistry) is carboxylic acid itself.

Carboxylic Acid Chemical Formula

The general formula of a carboxylic acid is CnH2n+1COOH (where n stands for the number of carbon atoms in the molecule minus 1). Note that O atoms are not linked together. The carboxyl group is the functional group of carboxylic acids. A carbonyl group (-C=O) and a hydroxyl group (-OH) are joined to form the carboxyl group.

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Structure of Carboxylic Acid

Carboxylic Acid CAS Number

Carboxylic acid has the CAS registry number (authentic numeric identifier which can contain up to 10 digits) 68603-87-2.

Carboxylic Acid ChemSpider ID

Carboxylic acid has the ChemSpider ID (ChemSpider is a free chemical structure database) 28536480.

Carboxylic Acid Chemical Classification

  • They are divided into monocarboxylic acid, dicarboxylic acid, and tricarboxylic acid based on the number of carboxyls (-COOH) groups present.
  • Depending on the kind of group (alkyl or aryl) connected to the (-COOH), they are divided into aliphatic and aromatic compounds.

Carboxylic Acid Color

Most carboxylic acids are “colourless” liquids with an unpleasant odour.

Carboxylic Acid Viscosity

The viscosity of carboxylic acids can’t be determined because it’s a functional group, not an element or compound.

Carboxylic Acid Boiling Point

Carboxylic acids have high boiling points compared to other compounds with comparable molar masses.

Carboxylic Acid Melting Point

The melting point of carboxylic acid doesn’t show a regular pattern with increasing molar mass. The ability of carboxylic acids to form “dimers” by hydrogen bonding between two carboxylic acid groups is an explanation for this absence of a clear trend.

Carboxylic Acid State at Room Temperature

At room temperature, all aromatic carboxylic acids are crystalline solids.

Carboxylic Acid Ionic/Covalent Bond

Carboxylic acid forms a covalent bond. They overlap and form a dimer in an aqueous environment because of their small size and strong intermolecular hydrogen bonds.

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H-Bonding in dimer

Carboxylic Acid Covalent radius

The covalent radius of carboxylic acid cannot be determined, as the covalent radius can only be calculated for any single atom.

Carboxylic Acid Electron Configurations

The representation shows the arrangement of electrons into the atomic orbitals, known as electronic configuration. Let us explain the electron configuration of carboxylic acid.

Molecules with at least one carboxyl functional group (COOH) are known as carboxylic acids. Since carboxylic acid is not an element, the electronic configuration can’t be stated.

Carboxylic Acid Oxidation State

The formal oxidation state of the carboxyl carbon in carboxylic acids and their derivatives is +3, which is the highest attainable in the order of organic functional groups. In carboxylic acid carboxyl group’s (-C=O) carbon atom is in a relatively high oxidation state.

Carboxylic Acid Acidity/Alkaline

Carboxylic acids are acidic in nature. In water, carboxylic acids can split to form hydronium and carboxylate ions. The resonance will effectively delocalize the negative charge, stabilizing the generated carboxylate ion.

Is Carboxylic Acid Odourless?

Unpleasant odours are found in aliphatic carboxylic acids with up to nine carbon atoms. In contrast, higher acids are odourless.

Carboxylic Acid Hydrates

Since carboxylic acid is not a compound, it does not result in hydrate formation.

Carboxylic Acid Crystal Structure

The formation of solid crystalline monolayers has been studied using X-ray and neutron diffraction. The unit cell diameters of the monolayer crystal structures are comparable to some close-packed planes of the bulk crystals, but the molecular configurations are different.

Carboxylic Acid Polarity and Conductivity

  • The carboxylic acid moiety is highly polar due to the polar organic functional group. The carbonyl (C=O) and hydroxyl (O-H) groups, which are strongly polarised, contribute to this polarity.
  • Since carboxylic acids are weak acids, they conduct electricity when present in solutions, but only at very low levels.

Carboxylic Acid Reaction with Acid

Carboxylic acid is itself a weak acid. Acids are used as dehydrating agents in the chemical reactions of carboxylic acid. Aromatic carboxylic acids undergo electrophilic substitution reactions like nitration, sulphonation, and halogenation in the presence of concentrated acids.

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Nitration of Aromatic Carboxylic Compound

Carboxylic Acid Reaction with Base

Carboxylic acids and bases react to produce the corresponding salts and water.

  • CH3COOH + NaOH  CH3COONa + H2O

Carboxylic Acid Reaction with Oxide

A metal carboxylate salt is produced when a metal oxide and a carboxylic acid react.

Metal oxide + Carboxylic acid → Metal carboxylate + Water

  • CaO(s) + 2 CH3COOH(aq) → Ca(CH3COO)2(aq) + H2O(l)

Carboxylic Acid Reaction with Metal

The corresponding salts are produced when carboxylic acids react with metals like K, Na, Mg, and Ca. The reaction releases H2 gas.

2CH3COOH + 2Na → CH3COONa + H2


Let us conclude that carboxylic acids are organic acids with a carboxyl functional group. These are weak acids that are used as precursors for various chemical reactions. They play a vital role in manufacturing solvents, polymers, food additives, and medicines.