1. What is the tetravalency of carbon?
Answer: Tetravalency of carbon refers to its ability to form four covalent bonds with other atoms, which allows it to create a wide variety of stable compounds.
2. Describe the shapes of simple molecules formed by carbon.
Answer: Simple molecules formed by carbon include methane (tetrahedral), ethene (planar with trigonal planar geometry around each carbon), and ethyne (linear).
3. What is hybridization in organic chemistry?
Answer: Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can form sigma bonds. For example, sp³ hybridization in methane, sp² in ethene, and sp in ethyne.
4. How are organic compounds classified based on functional groups?
Answer: Organic compounds are classified based on functional groups such as alcohols (–OH), aldehydes (–CHO), ketones (C=O), carboxylic acids (–COOH), amines (–NH₂), and others.
5. What are homologous series in organic chemistry?
Answer: Homologous series are families of organic compounds with the same functional group and similar chemical properties, where each successive member differs by a CH₂ unit.
6. Explain structural isomerism.
Answer: Structural isomerism occurs when compounds have the same molecular formula but different structural formulas, such as chain isomerism, position isomerism, and functional group isomerism.
7. What is stereoisomerism?
Answer: Stereoisomerism refers to compounds with the same molecular formula and connectivity of atoms but different spatial arrangements, including geometric (cis-trans) isomerism and optical isomerism.
8. How are organic compounds named using IUPAC nomenclature?
Answer: IUPAC nomenclature names organic compounds based on the longest carbon chain, the positions of functional groups, and the types of substituents, following a set of standardized rules.
9. What is homolytic fission in a covalent bond?
Answer: Homolytic fission is the breaking of a covalent bond where each bonded atom retains one of the shared electrons, resulting in the formation of two free radicals.
10. What is heterolytic fission in a covalent bond?
Answer: Heterolytic fission is the breaking of a covalent bond where one atom retains both of the shared electrons, resulting in the formation of a cation and an anion.
11. What are free radicals in organic chemistry?
Answer: Free radicals are highly reactive species with an unpaired electron, formed by homolytic fission of a covalent bond.
12. Define carbocations and carbanions.
Answer: Carbocations are positively charged carbon species (R₃C⁺), while carbanions are negatively charged carbon species (R₃C⁻).
13. Discuss the stability of carbocations.
Answer: The stability of carbocations increases with the number of alkyl groups attached to the positively charged carbon due to inductive and hyperconjugation effects. Order of stability: tertiary > secondary > primary > methyl.
14. What are electrophiles and nucleophiles?
Answer: Electrophiles are electron-deficient species that seek electrons (e.g., H⁺, NO₂⁺), while nucleophiles are electron-rich species that donate electrons (e.g., OH⁻, NH₃).
15. Explain the inductive effect in a covalent bond.
Answer: The inductive effect is the electron-withdrawing or electron-donating effect transmitted through sigma bonds due to the electronegativity of atoms or groups attached to the carbon chain.
16. What is the electromeric effect?
Answer: The electromeric effect is the temporary shifting of electrons in a multiple bond towards one atom under the influence of an attacking reagent, typically seen in reactions involving pi bonds.
17. Describe resonance in organic molecules.
Answer: Resonance is the delocalization of electrons in conjugated systems, where electrons are spread over several atoms, leading to the stabilization of the molecule.
18. What is hyperconjugation?
Answer: Hyperconjugation is the delocalization of electrons from C-H or C-C sigma bonds adjacent to a positively charged carbon atom (carbocation) or a double bond, stabilizing the molecule.
19. What are the common types of organic reactions?
Answer: Common types of organic reactions include substitution reactions (replacement of an atom or group), addition reactions (adding atoms or groups to double or triple bonds), elimination reactions (removal of atoms or groups to form double or triple bonds), and rearrangement reactions (reorganization of the structure).
20. Explain the difference between structural and stereoisomerism.
Answer: Structural isomerism involves different connectivity of atoms within molecules, whereas stereoisomerism involves the same connectivity but different spatial arrangements of atoms.