Tiêu đề Chap. 5.pdf ✅

5.1 INTRODUCTION; NOMENCLATURE AND STRUCTURE OF CARBONYL GROUP 1. Carbonyl compounds impart fragrance to several natural substances. In this regard, select the correctly matched : (a) Cinnamaldehyde-cinnamon (b) Salicylaldehyde-meadow sweet (c) Vanilin-vanilla beans (d) all of these 2. IUPAC name of is : (a) Cyclohexanal (b) Cyclohexane carbaldehyde (c) Cyclohexyl carbaldehyde (d) None of these 3. IUPAC name of CH CH C O 3 2 CH2CHO || is: (a) 1-formyl-3-pentanone (b) 3-oxopentanal (c) Pentan-1-al-3-one (d) none of these 4. IUPAC name of OHC CH CH CH CHO — — — CHO | 2 2 — is: (a) 3-formylpentandial (b) 1,3,5-hexantrial (c) propane-1,2,3-tricarbaldehyde (d) none of these 5. Carbonyl carbon atom behaves as : (a) Lewis acid (b) Lewis base (c) Sometimes acid and sometimes base (d) Neither as acid nor as base 6. Formic acid is not a representative member of the carboxylic acids because : (a) it is the first member of the series (b) it does not contain in alkyl group 464 Elementary Organic Chemistry for Medical [A] Aldehydes and Ketones CHO Aldehydes, Ketones and Carboxylic Acids 5 Level-1
(c) it is a gas (d) it contains an aldehydic group while the other acids not have the aldehydic acid group 7. Carboxylic acids do not give the characteristic properties of : (a) C O group (b) —COOH group (c) alkyl group (d) none of these 8. Which of the following is not the functional isomer of monocarboxylic acid ? (a) Amide (b) Ester (c) Hydroxy aldehyde (d) Hydroxy ketone 9. What is the main reason for the fact that carboxylic acids can undergo ionization ? (a) Absence of alpha-hydrogen (b) Resonance stabilization of the carboxylate ion (c) High reactivity of alpha-hydrogen (d) Hydrogen bonding 10. Which is the IUPAC name for the following compound ? (a) 2-Oxohexanoic acid (b) 5-Oxohexanoic acid (c) Methyl butyroxo ketone (d) 4-Ketopentanoic acid 11. Which structures are correctly named ? (a) (b) (c) (d) 12. What is the IUPAC name for ? (a) 2,3-Dimethylbutyl acetate (b) 2,3-Dimethyl-4-oxoethanal (c) 2,3-Dimethylbutyl methanoate (d) 2,3-Dimethylbutyl methylate 5.2 METHODS OF PREPARATION OF ALDEHYDES AND KETONES 13. PhCH2OH PCC (pyridinium chlorochromate) in methylene chloride product (a) benzophenone (b) benzoic acid (c) benzaldehyde (d) benzyl chloride 14. In which of the following reactions, product will be aldehyde ? (a) CH C == CH C C CH 3 H 3 2 3 5 (ii) H O/Zn (i) O 2 3 (b) CH3 CH CH2 CO/H CO CO) 2 2 8 / ( (c) CH3 CH CH2 air/CuCl PdCl HOH 2 2 / (d) CH3 C CH HOH/HgSO4 H2SO4 / Aldehydes, Ketones and Carboxylic Acids 465 OH O O O Formic acid OH OH O O Acrylic acid HO OH O O OH Malonic acid OH O Methacrylic acid O O

22. What are the starting materials needed for the following reaction? (a) (b) (c) (d) 23. Product of the reaction is : (a) (b) (c) (d) 24. Which compound is formed when the enolate of 2-methylcyclohexanone, formed from lithium diisopropylamide (LDA), reacts with methyl iodide? (a) a (b) b (c) c (d) d 25. Which of the following compounds is a hydrazone ? (a) (b) (c) (d) 26. The compound : HOCH CH CH CH CH || O 2 2 2 2 can form a hemiacetal by reacting with itself in solution. What is the structure of this hemiacetal? Aldehydes, Ketones and Carboxylic Acids 467 CH3 N H HO NH2 CH3 N H—N OH CH3 O O OH a b c d NHNH2 N CH3 CH3 NH—NH N—NH2 O + OH HO OH + O O CH3 2 NH → pH 4.5 O + OH OH O + OH O HCl → O O