-oyl halide halocarbonyl- Amide $R-CONH_2$ Derivative of carboxylic acid where the -OH is replaced by an amino group (-NH2, -NHR, -NR2). -amide carbamoyl- Nitrile $R-C \equiv N$ Contains a cyano group (-C≡N). Triple bond between C and N. -nitrile cyano- Nitro Compound $R-NO_2$ Contains a nitro group (-NO2) bonded to an alkyl or aryl group. - nitro- Sulfide (Thioether) $R-S-R'$ Sulfur analog of ether, contains a sulfur atom bonded to two alkyl or aryl groups. - alkylthio- Sulfonic Acid $R-SO_3H$ Contains a sulfonyl hydroxyl group. Strong acid. -sulfonic acid sulfo-

3.3 IUPAC Naming Rules Summary

Parent Chain: Find longest continuous carbon chain containing the highest priority functional group.
Numbering: Number the parent chain to give the highest priority functional group the lowest possible number. If a tie, give substituents the lowest numbers.
Substituents: Identify and name all substituents.
Alphabetization: List substituents alphabetically (ignoring prefixes like di-, tri-, sec-, tert-).
Combine: Position numbers, prefixes (if any), substituent names, parent chain name, and functional group suffix.
Punctuation: Hyphens for numbers-words, commas for numbers-numbers.

4. Reaction Mechanisms

4.1 Nucleophiles & Electrophiles

Nucleophile: Electron-rich species, donates electron pair (Lewis base). Often negatively charged or has lone pair. (e.g., $OH^-$, $H_2O$, $NH_3$).
Electrophile: Electron-deficient species, accepts electron pair (Lewis acid). Often positively charged or has partial positive charge. (e.g., $H^+$, $Br^+$, carbonyl carbon).

4.2 Types of Reactions

Substitution: One atom/group replaced by another.
- Nucleophilic Substitution ($SN1$, $SN2$).
- Electrophilic Aromatic Substitution ($EAS$).
Addition: Atoms/groups added across a double/triple bond.
- Electrophilic Addition (e.g., $HBr$ to alkene).
- Nucleophilic Addition (e.g., to carbonyls).
Elimination: Atoms/groups removed, forming a double/triple bond.
- $E1$, $E2$.
Rearrangement: Atoms/groups migrate within a molecule.

4.3 Acid-Base Chemistry

Brønsted-Lowry: Acid donates $H^+$, Base accepts $H^+$.
Lewis: Acid accepts electron pair, Base donates electron pair.
$pK_a$: Measure of acid strength. Lower $pK_a$ = stronger acid.
Factors affecting acidity: Electronegativity, resonance, inductive effect, hybridization.

5. Spectroscopy

5.1 Infrared (IR) Spectroscopy

Identifies functional groups based on vibrational frequencies.
Key absorptions:
- $O-H$ (alcohols): Broad, strong, $3200-3600 cm^{-1}$
- $N-H$ (amines): Medium, $3300-3500 cm^{-1}$ (1 or 2 peaks)
- $C=O$ (carbonyls): Strong, $1650-1780 cm^{-