Work Book (Phase - IV) Subjective: Board Type Questions 1. Which bond is more polar in the following pairs of molecules? (a) H3C – H, H3C – Br (b) H3C – NH2, H3C – OH (c) H3C – OH, H3C – SH 2. Write resonance structures of (a) CH3COO– and (b) C6H5NH2. Show the movement of electrons by curved arrows. 3. Write the resonance structures of CH2 = CH – CHO and arrange them in order of decreasing stability. 4. Give reasons why the following two structures (I and II) cannot be the major contributors to the real structure of CH3COOCH3. 5. Using curved arrow notation, show the formation of reactive intermediates when the following covalent bonds undergo heterolytic cleavage. (a) CH3 – SH (b) CH3 – CN (c) CH3 – Cu 6. Giving proper justification, categories the following molecules/ions as nucleophile or electrophile: 7. Identify the electrophilic centres in the following: CH2 = C = O, CH3CN, CH3I 8. What is the relationship between the members of following pairs of structures? Are they identical, structural or geometrical isomers, or resonance contributors? (a) (b) (c) (d) 9. What type of aromatic compounds are present as particulates in the air? 10. Why ‘photochemical smog’ is so called? 11. Draw the structure of the tautomer of phenol and write its IUPAC name. 12. Arrange the following in increasing order of C – C bond length: C2H6, C2H4, C2H2. 13. Name the alkyl groups derived from isobutene. 14. Select electrophiles out of the following: H+, Na+, Cl–, C2H5OH, AlCl3, SO3, CN–, 15. Arrange the following: (i) in order of increasing stability. (ii) in order of decreasing stability. (iii) in order of increasing stability. 16. Which is expected to be more stable, O2NCH2CH2O– or CH3CH2O– and why? 17. Indicate σ- and π-bonds in the following compounds: (a) C6H6 (b) C6H12 (c) CH2Cl2 (d) CH2 = C = CH2 (e) CH3NO2 (f) HCONHCH3 18. A hydrocarbon has the molecular mass 70. Write all the possible structural isomers and give their IUPAC names. 19. What is the nature of ‘photochemical smog’? 20. Explain inductive and electromeric effect with examples. 21. Explain hyperconjugation effect. 22. What is COD? Which chemical substance is generally used in its measurement? 23. For the following bond cleavages, use curved arrows to show the electron flow and classify each as homolysis or heterolysis. Identify reactive intermediate products as free radical, carbocation and carbanion. (a) (b) (c) (d) 24. Draw the resonance structures of the following carbocation? Use curved arrows to show how one structure is converted into another. 25. (a) Write the resonance structures of diazomethane (CH2N2). (b) Give the hybridized state of carbon and each N in each structure. (c) How does the H – C – H bond angle in the hybrid compare with the bond angles predicted from each contributing structure? 26. With proper justification, arrange the following in order of increasing stability. 27. Give the IUPAC name for the a