Unit 13: Fundamental Principles of Organic Chemistry (10 Teaching Hours)
-
IUPAC Nomenclature of Organic Compounds (up to Chain Having 6 Carbon Atoms)
- Rules
- Identify the longest carbon chain as the parent (e.g., methane: 1C, ethane: 2C, up to hexane: 6C).
- Number the chain to give the lowest numbers to functional groups or substituents.
- Name functional groups (e.g., -OH: ol, -CHO: al, -COOH: oic acid) and substituents (e.g., methyl, chloro) with appropriate prefixes (di-, tri-).
- Examples: CH₃CH₂OH (ethanol), CH₃CH₂CH₂CHO (butanal), CH₃CH(CH₃)CH₂CH₃ (2-methylbutane).
- Figure 1: IUPAC Nomenclature Examples (Diagram showing naming of ethanol and 2-methylbutane).
- Rules
-
Qualitative Analysis of Organic Compounds (Detection of N, S, and Halogens by Lassaigne’s Test)
- Lassaigne’s Test
- Organic compound fused with sodium to convert N, S, and halogens into ionic forms for detection.
- Nitrogen: Forms NaCN, detected as Prussian blue with FeSO₄ and HCl: NaCN + FeSO₄ → Fe₄[Fe(CN)₆]₃.
- Sulphur: Forms Na₂S, detected as violet color with sodium nitroprusside: Na₂S + Na₂[Fe(CN)₅NO] → Na₄[Fe(CN)₅NOS].
- Halogens: Forms NaX (X = Cl, Br, I), detected as AgX precipitate with AgNO₃ (e.g., AgCl: white, AgBr: pale yellow, AgI: yellow).
- Figure 2: Lassaigne’s Test Procedure (Diagram showing sodium fusion and detection steps for N, S, halogens).
- Lassaigne’s Test
-
Isomerism in Organic Compounds
- Definition and Classification
- Isomerism: Compounds with the same molecular formula but different structures or spatial arrangements.
- Types: Structural (constitutional) isomerism and stereoisomerism (geometrical, optical).
- Structural Isomerism and Its Types
- Chain Isomerism: Different carbon skeletons (e.g., n-butane vs. isobutane: C₄H₁₀).
- Position Isomerism: Different positions of functional group (e.g., 1-propanol vs. 2-propanol: C₃H₈O).
- Functional Isomerism: Different functional groups (e.g., ethanol vs. dimethyl ether: C₂H₆O).
- Metamerism: Different alkyl groups around a functional group (e.g., diethyl ether vs. methyl propyl ether: C₄H₁₀O).
- Tautomerism: Dynamic isomerism with shifting H atom and bond (e.g., keto-enol: CH₃COCH₃ ⇌ CH₂=C(OH)CH₃).
- Figure 3: Types of Structural Isomerism (Diagram showing examples of chain, position, and functional isomers).
- Geometrical Isomerism (Cis & Trans)
- Occurs in alkenes or cyclic compounds due to restricted rotation around double bonds or rings (e.g., cis-2-butene vs. trans-2-butene).
- Figure 4: Geometrical Isomerism (Diagram showing cis and trans isomers of 2-butene).
- Optical Isomerism (d & l Form)
- Occurs in chiral compounds with an asymmetric carbon, rotates plane-polarized light (e.g., d-lactic acid and l-lactic acid: C₃H₆O₃).
- Figure 5: Optical Isomerism (Diagram showing chiral carbon and d/l forms of lactic acid).
- Definition and Classification
-
Preliminary Idea of Reaction Mechanism
- Homolytic and Heterolytic Fission
- Homolytic Fission: Bond breaks symmetrically, forming two free radicals (e.g., Cl–Cl → 2Cl·).
- Heterolytic Fission: Bond breaks asymmetrically, forming a cation and anion (e.g., CH₃–Br → CH₃⁺ + Br⁻).
- Figure 6: Homolytic and Heterolytic Fission (Diagram showing bond cleavage in Cl₂ and CH₃Br).
- Electrophiles, Nucleophiles, and Free Radicals
- Electrophiles: Electron-deficient species that accept electrons (e.g., H⁺, carbocations).
- Nucleophiles: Electron-rich species that donate electrons (e.g., OH⁻, NH₃).
- Free Radicals: Neutral species with unpaired electrons (e.g., CH₃·).
- Inductive Effect: +I and –I Effect
- +I Effect: Electron-donating groups increase electron density (e.g., –CH₃, –C₂H₅).
- –I Effect: Electron-withdrawing groups decrease electron density (e.g., –NO₂, –Cl).
- Resonance Effect: +R and –R Effect
- +R Effect: Groups donate electrons via conjugation (e.g., –OH, –NH₂).
- –R Effect: Groups withdraw electrons via conjugation (e.g., –CHO, –NO₂).
- Figure 7: Inductive and Resonance Effects (Diagram showing electron movement in molecules with +I/–I and +R/–R groups).
- Homolytic and Heterolytic Fission