karboxýlhópur
The karboxýlhópur, also known as a carboxyl group, is a functional group in organic chemistry. It consists of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. Its chemical formula is typically represented as -COOH. This combination of atoms gives the carboxyl group its characteristic acidic properties. When the carboxyl group is attached to a hydrocarbon chain or an aromatic ring, it forms a carboxylic acid. These compounds are weak acids because the hydrogen atom of the hydroxyl group can be released as a proton (H+). The remaining group, known as the carboxylate anion (-COO-), is resonance-stabilized, which contributes to the acidity. Carboxylic acids are widely found in nature, such as in acetic acid (vinegar) and citric acid (lemons). They play crucial roles in biological systems, forming the building blocks of proteins (amino acids) and fatty acids. The reactivity of the carboxyl group allows it to undergo various chemical reactions, including esterification, amide formation, and reduction. The presence of a carboxyl group significantly influences the physical properties of a molecule, such as its solubility in water and its boiling point.