Understanding Acyl Compounds and Carboxylic Acid Derivatives Quiz

Esters are named by replacing the “-ic acid” ending of the parent carboxylic acid with “-ate.” The alkyl group derived from the alcohol is written as a separate word before the alkanoate portion. This naming method reflects the ester’s formation from both an alcohol and an acid.

Acid halides are named by replacing the “-ic acid” ending of the parent carboxylic acid with “-yl halide.” This indicates that the hydroxyl group has been replaced by a halogen. This naming convention clearly identifies both the carbon chain and the attached halogen atom.

Ethanoyl chloride is commonly referred to as acetyl chloride. Both names describe the same acid chloride derived from acetic acid. The compound is highly reactive and used frequently in acylation reactions. The other options describe acids or unrelated chlorinated compounds, making them incorrect.

Acid anhydrides are named by replacing the word “acid” with “anhydride” in the parent acid name. For mixed anhydrides, the names of both acids are listed alphabetically before “anhydride.” This system reflects their formation from two carboxylic acid molecules with loss of water.

Ethanoic anhydride is more commonly known as acetic anhydride. This common name is widely used in laboratories and industry. It is derived from two molecules of acetic acid and is an important reagent for acetylation reactions in organic synthesis.

Benzoic butanoic anhydride is a mixed acid anhydride formed from benzoic acid and butanoic acid. It contains two different acyl groups connected through an anhydride linkage. It is not an ester, mineral acid, or alcohol, making mixed anhydride the correct classification.

When two ethyl groups are attached to the nitrogen atom of propanamide, the compound is named N,N-diethylpropanamide. The “N,N-” prefix indicates both substituents are bonded to nitrogen rather than the carbon chain, ensuring correct structural interpretation and systematic naming.

Acetonitrile is the common name for ethanenitrile, a two-carbon nitrile. It is widely used as a solvent in laboratories. The other options represent nitriles with different carbon chain lengths and therefore do not correspond to acetonitrile’s molecular structure.

Ketenes are named as alkene-substituted ketones because their structure contains a carbonyl group adjacent to a carbon-carbon double bond. This naming reflects both functional components of the molecule and distinguishes ketenes from simple alkenes, alkanes, or aldehydes.

Formic acid is the simplest carboxylic acid, consisting of one carbon atom bonded to a hydroxyl group and a carbonyl group. Its molecular formula is HCOOH. The other listed formulas represent salts, alcohols, or inorganic acids, none of which match the structure or functional group characteristics of formic acid.

Acetic acid is commonly known as vinegar in everyday usage. Vinegar is an aqueous solution of acetic acid and is widely used in food preparation and cleaning. The other options listed do not represent acetic acid or share its chemical composition, making vinegar the only correct and commonly accepted alternative name.

Methyl ethanoate is produced by the reaction between methanol and ethanoic acid, forming an ester functional group. It is not an alkane, alcohol, or carbene because it contains a carbonyl group bonded to an oxygen atom. The presence of this linkage defines the compound as an ester.

A butanamide molecule with a methyl group attached to the third carbon is named 3-methylbutanamide. IUPAC rules require numbering the carbon chain to give the substituent the lowest possible position. This name accurately reflects both chain length and substituent placement.

A six-membered cyclic amide containing a nitrogen atom at position two is named 2-azacyclohexanone. The prefix “aza” indicates nitrogen substitution, while the numbering identifies its position in the ring. This systematic naming ensures clarity in heterocyclic compound identification.

Compounds containing the R–CN functional group are classified as nitriles. They are named using the suffix “-nitrile,” counting the nitrile carbon as part of the longest chain. If nitrile is not the highest priority group, it is indicated using the “cyano-” prefix.

Acyl and acyl-like compounds contain a carbonyl group attached to another atom such as oxygen, nitrogen, or halogen. Carboxylic acids, esters, acid chlorides, amides, and anhydrides all share this defining structural feature. The other options lack the carbonyl-based acyl functionality and therefore do not belong to this classification within organic chemistry.

Carboxylic acids are named by replacing the terminal “-ane” of the parent alkane with the suffix “-oic acid.” This IUPAC naming rule ensures consistency and clarity by clearly identifying the presence of the carboxyl functional group while preserving information about the carbon chain length.

Butanoyl fluoride is an acid fluoride formed by replacing the hydroxyl group of butanoic acid with a fluorine atom. It belongs to the acid halide family. The other options describe alcohols or acids, which lack the defining halogen-substituted acyl functional group.

Cyclic amides are known as lactams. This term parallels the naming of cyclic esters as lactones. Lactams contain a nitrogen atom within the ring and an amide functional group, making them important structural motifs in pharmaceuticals and biologically active compounds.

tert-Butyl butanoate is already correctly named using ester nomenclature rules. The tert-butyl group represents the alkyl portion from the alcohol, while butanoate represents the acid-derived portion. The alternative options describe esters with different alkyl or acid components and therefore do not correspond to the given compound.

A five-membered cyclic ester containing one oxygen atom in the ring is named 2-oxacyclopentanone. This name reflects both the heteroatom substitution and the carbonyl group. The other options either describe open-chain compounds or lack the correct ring structure required for this classification.

Methanoyl chloride is also known as formyl chloride. It is derived from formic acid by replacing the hydroxyl group with a chlorine atom. The alternative options describe alkyl chlorides rather than acid chlorides and therefore do not represent the same functional group or molecular structure.

Cyclic anhydrides are named as derivatives of their corresponding carboxylic acids. They form when a dicarboxylic acid undergoes intramolecular dehydration. Naming them this way preserves the relationship to the parent acid while indicating the presence of an anhydride functional group.

Amides are named by replacing the “-oic acid” ending of the corresponding carboxylic acid with “-amide.” Substituents attached to the nitrogen atom are indicated using the prefix “N-.” This system clearly distinguishes amides from acids and identifies nitrogen substitution.

Phenyl methanoate has the same structure as methyl benzoate, making methyl benzoate its common name. The compound consists of a benzoate group bonded to a methyl group through an ester linkage. The other options describe different functional groups or molecular arrangements that do not match this structure.

Cyclic esters are called lactones. This term is widely accepted in organic chemistry and refers specifically to ester groups incorporated within a ring structure. Lactones commonly form from hydroxy acids through intramolecular esterification, giving them distinct chemical and physical properties compared to open-chain esters.

2-Oxacycloheptanone represents a cyclic ester containing seven atoms in the ring. According to heterocyclic naming conventions, it is systematically named based on ring size and oxygen position. The other options describe ketones or linear molecules that do not match the cyclic ester structure shown.

The molecular formula C₂H₅CONH₂ corresponds to ethanamide. Acetamide has one fewer carbon atom and a different molecular formula. The remaining options represent aldehydes or amines, which have different functional groups and structural characteristics than amides.