The hydroxyl (-OH) group is the key feature of alcohols. Other groups such as aldehydes, amines, and esters contain different substituents and do not present an -OH group directly attached to carbon.

Ethers are characterized by the structure R-O-R', where an oxygen atom connects two alkyl or aryl groups. This distinguishes them from other functional groups that have different bonding patterns.

Aldehydes are defined by having the carbonyl group at the end of a carbon chain, which means at least one hydrogen is attached to the carbonyl carbon. Ketones feature the carbonyl group within the carbon chain.

Carboxylic acids feature a carbonyl group and a hydroxyl group bonded to the same carbon, forming the -COOH group. This combination is not present in esters, ketones, or alcohols.

Amines are recognized by the presence of an amino (-NH2) group attached to a carbon framework. This distinguishes them from groups like ethers, aldehydes, or alcohols, which have differing functional groups.

Ketones have a carbonyl carbon that is bonded to two other carbon groups, unlike aldehydes, which have at least one hydrogen attached. This difference is essential in determining their reactivity and properties.

The formula R-COOH represents carboxylic acids, defined by the carboxyl functional group. Esters, ketones, and alcohols have distinct structures with different functional groups.

Esters are characterized by a carbonyl group bonded to an oxygen that is connected to another carbon group (R-COO-R'). This structure clearly differentiates them from ethers, alcohols, and amides.

Amines possess a lone pair of electrons on the nitrogen, enabling them to function both as nucleophiles and bases. Other groups, such as alcohols and ketones, do not exhibit this dual ability to the same extent.

Alcohols contain an -OH group that can both donate and accept hydrogen bonds, making them particularly adept at hydrogen bonding. Other functional groups do not possess the same combination of hydrogen bond donor and acceptor capabilities.

Carboxylic acids are acidic because their conjugate base, the carboxylate ion, is stabilized by resonance across two oxygen atoms. This resonance effect is not present to the same degree in alcohols, aldehydes, or amines.

The carbonyl group pulls electron density away from adjacent carbons due to the high electronegativity of oxygen. This electron-withdrawing effect influences the reactivity of nearby atoms in the molecule.

The reaction between a carboxylic acid and an alcohol produces an ester through an esterification process. This reaction typically results in the formation of water as a by-product.

Aldehydes are characterized by having at least one hydrogen attached to the carbonyl carbon, whereas ketones have two carbon groups attached. This difference is critical for their reactivity and naming.

Amides contain a carbonyl group (C=O) that is directly bonded to a nitrogen atom. This linkage differentiates them from esters, ketones, and aldehydes.

Upon deprotonation, carboxylic acids form carboxylate ions that benefit from resonance stabilization over two oxygen atoms. Although esters exhibit resonance, their stabilization is not as effective as that of carboxylate ions.

An electron-withdrawing group pulls electron density away from the carbonyl carbon through the inductive effect, thereby increasing its electrophilicity. This heightened positive character makes the carbonyl more susceptible to nucleophilic attack.

Resonance delocalizes the electron density in the carbonyl group, imparting partial single-bond character to the C=O bond. As a result, the bond length is slightly longer than that of a pure double bond.

Conjugation with an aromatic ring allows electron density to be spread over a larger structure, which generally decreases the electrophilic nature of the carbonyl carbon. This delocalization reduces its reactivity toward nucleophiles compared to non-conjugated carbonyl systems.

In nucleophilic acyl substitution, the rate-determining step is typically the collapse of the tetrahedral intermediate, during which the leaving group is expelled. The initial nucleophilic attack is generally fast and reversible.