Repeated Chemistry Questions for 2nd PUC (Karnataka)

High-Yield Topics from Past Exams

Based on Karnataka 2nd PUC Chemistry question paper patterns, these concepts appear frequently:

1. Definitions: Mole, Molarity, Molality, Normality, Avogadro's number, Equivalent weight
2. Hybridization: sp, sp², sp³ with examples (BeCl₂, BF₃, CH₄, NH₃, H₂O); VSEPR shapes
3. Alkanes: Preparation (Wurtz, Kolbe, decarboxylation, hydrogenation); properties (halogenation mechanism, combustion, pyrolysis)
4. Electrophilic Addition to Alkenes: Mechanism (carbocation intermediate); Markovnikov/anti-Markovnikov (peroxide effect); examples: HBr, H₂SO₄, H₂O, X₂, HX
5. Alcohol Classification: 1°/2°/3°; Lucas test, oxidation (PCC, KMnO₄, CrO₃), dehydration (E1/E2)
6. Aldehyde/Ketone Prep: Oxidation of alcohols, Rosenmund, Stephen, Gattermann-Koch, Friedel-Crafts acylation; properties: nucleophilic addition, Cannizzaro, aldol
7. Nucleophilic Substitution (SN1/SN2): Mechanism, kinetics, stereochemistry, carbocation stability, solvent effects; example: CH₃Br + OH⁻
8. Resonance: Definition, rules, examples (benzene, carboxylate, nitrate, enolate); resonance hybrid vs. contributors
9. Aromaticity & Benzene: Hückel rule (4n+2), resonance energy, electrophilic substitution (nitration, sulfonation, halogenation, Friedel-Crafts) mechanisms
10. Biomolecules: Carbohydrates (glycosidic link, mutarotation), proteins (peptide bond, denaturation), nucleic acids (base pairing, replication)

Exam Strategy

• Master mechanisms with curved arrows
• Practice named reactions (conditions, reagents, products)
• Solve 10-year papers; focus on 3- & 5-mark questions
• NCERT + PUC textbook = core