What functional group has an –OH on a saturated carbon?	Alcohol (–OH). Classified as 1°, 2°, or 3° by the number of carbons on the –OH carbon.
What is the general structure of an aldehyde?	R–CHO. Carbonyl (C=O) bonded to at least one hydrogen, always terminal.
How does a ketone differ from an aldehyde?	A ketone has the carbonyl bonded to two carbon groups (R–CO–R'), making it internal rather than terminal.
What functional group defines carboxylic acids?	The carboxyl group (–COOH): a carbonyl and hydroxyl on the same carbon. General formula R–COOH, typical pKa 2–5.
What is an ester and how is it formed?	R–COO–R'. Formed by Fischer esterification: acid-catalyzed condensation of a carboxylic acid and an alcohol, releasing water.
What is the functional group of an ether?	An oxygen bonded to two alkyl or aryl groups (R–O–R'). Relatively unreactive; commonly used as solvents.
How do 1°, 2°, and 3° amines differ?	By the number of carbon groups on nitrogen: R–NH₂ (1°), R₂NH (2°), R₃N (3°).
What is an amide and why is its C–N bond unusually short?	R–CO–NR'R''. The nitrogen lone pair delocalizes into the carbonyl, giving the C–N bond partial double-bond character.
What functional group do thiols contain?	A sulfhydryl group (–SH). Thiols have strong odors and can be oxidized to disulfide bonds (R–S–S–R).
What IUPAC suffix names alcohols?	–ol (e.g., ethanol, propan-1-ol). The position of –OH is indicated by a locant.
What IUPAC suffix names aldehydes?	–al (e.g., ethanal, propanal). The aldehyde carbon is always C-1, so no locant is needed.
What IUPAC suffix names ketones?	–one (e.g., propanone, butan-2-one). A locant indicates the carbonyl position.
What IUPAC suffix names carboxylic acids?	–oic acid (e.g., ethanoic acid). The carboxyl carbon is always C-1.
What is an acid anhydride?	R–CO–O–CO–R'. Essentially two carboxylic acids minus water. More reactive than esters but less than acid chlorides toward nucleophilic acyl substitution.
What is an acid chloride and why is it highly reactive?	R–COCl. Chloride is an excellent leaving group, making acid chlorides the most reactive carboxylic acid derivatives.
What is a nitrile?	R–C≡N (carbon–nitrogen triple bond). Named with the suffix –nitrile; the nitrile carbon is counted in the parent chain.
What functional group defines alkenes?	A C=C double bond. Alkenes undergo electrophilic addition because the pi electrons act as a nucleophilic site.
What functional group defines alkynes?	A C≡C triple bond (one sigma, two pi). Terminal alkynes are weakly acidic (pKa ~25) due to sp hybridization.
What is an acetal and how is it formed?	R₂C(OR')₂. Formed by reacting an aldehyde or ketone with two equivalents of alcohol under acid conditions. Stable under basic conditions; used as carbonyl protecting groups.
What is a hemiacetal?	R₂C(OH)(OR'). Intermediate from adding one equivalent of alcohol to a carbonyl. Generally unstable in open-chain form but stable in cyclic sugars.
What is an imine (Schiff base)?	R₂C=NR'. Formed by condensation of a primary amine with an aldehyde or ketone, losing water.
Rank acid chloride, anhydride, ester, and amide by reactivity toward nucleophilic acyl substitution.	Acid chloride > anhydride > ester > amide. Reactivity decreases as the leaving group worsens and heteroatom resonance stabilizes the carbonyl.
What is a phenol and how does its acidity compare to alcohols?	–OH bonded to a benzene ring. Phenols (pKa ~10) are more acidic than alcohols (pKa ~16–18) because the phenoxide ion is resonance-stabilized.
What is an epoxide and why is it reactive?	A three-membered cyclic ether. Severe ring strain (~60° vs. ideal ~109.5°) makes it far more reactive than typical ethers.
What is a lactone?	A cyclic ester from intramolecular esterification of a hydroxy acid. Named by ring size: β (4), γ (5), δ (6). Five- and six-membered lactones form readily.