Tiêu đề Neet proof reading chapter -2 aliphatic and aromatic hydrocarbons ✅

2.1 GENERAL INTRODUCTION, CLASSIFICATION AND STRUCTURE 1. In cyclopropane, cyclobutane and cyclohexane, the common group is : (a) — | | C — (b) — CH2 — (c) — CH3 (d) — | CH— 2. Among the following, which is not a hydrocarbon ? (a) CNG (b) LPG (c) Paraffin wax (d) Polyester 3. Select the odd one : (a) polythene (b) polypropylene (c) polystyrene (d) buna-s 4. As the molecular mass of hydrocarbons increases, the ratio of number of H and C atoms : (a) decreases (b) increases (c) remains same (d) none of these 5. Which of the following does not necessarily represent a hydrocarbon ? (a) C C C | — | | — (b) — | | — — | | C O C— (c) — | | C— (d) H — C C — 6. Among the values of bond angles given below, which is not possible for a hydrocarbon ? (a) 120° (b) 109° (c) 180° (d) 90° 7. Which of the following is not a class of hydrocarbons ? (a) Paraffins (b) Olefins (c) Arenes (d) None of these 162 Elementary Organic Chemistry for Medical Level-1 Hydrocarbons (Aliphatic and Aromatic Hydrocarbons) 2
8. The structure of isobutyl group in an organic compound is : (a) CH CH CH CH 3 3 2 — — (b) CH3 — CH CH2 CH3 | — — (c) CH3 — CH2 — CH2 — CH2 — (d) CH C CH CH 3 3 3 — — | | 9. How many secondary hydrogens are there in the following alkane ? CH CH CHCH CH CH 3 3 2 2 3 (a) 1 (b) 2 (c) 4 (d) 9 10. How many compounds with the formula C7H16 (heptanes) contain a single tertiary carbon atom ? (a) 2 (b) 3 (c) 4 (d) 5 11. What is the simplest alkane, that is, the one with the smallest molecular weight, which possesses primary, secondary and tertiary carbon atoms ? (a) 2-methylpropane (b) 2-methylbutane (c) 2-methylpentane (d) 3-methylpentane 12. Pick out the alkane which differs from the other members of the group : (a) 2,2-dimethylpropane (b) pentane (c) 3-methylbutane (d) 2,2-dimethylbutane 2.2 ALKANES [A] General Introduction 13. The formula of Marsh gas is : (a) CH4 (b) C2H6 (c) C2H4 (d) C2H2 14. Initially, alkanes were also named as paraffins due to : (a) low chemical reactivity (b) solid state nature (c) high chemical reactivity (d) none of these 15. In alkanes approximate value of C — C and C — H bond lengths respectively are : (a) 154 pm, 112 pm (b) 154 pm, 154 pm (c) 112 pm, 154 pm (d) 112 pm, 112 pm 16. Geometry of carbon atoms in alkanes is : (a) linear (b) triangular (c) tetrahedral (d) any of these [B] Methods of Preparation 17. ; Major-product (A) is : Hydrocarbons 163 C—O K O s r → electrolysis (A) (Major)
(a) (b) (c) (d) 18. ; Product (A) is: (a) (b) (c) (d) 19. How many different Grignard reagents may react with alcohol (Excluding stereoisomer) to give n-butane ? (a) 1 (b) 2 (c) 3 (d) 4 20. In the reaction CH CH OH i TsCl ii LiAlH 3 2 4 — — [ ] ( ) ( ) P ; Product [P] will be : (a) H2C CH2 (b) CH3CH2CH2CH3 (c) CH3CH3 (d) CH3CH CHCH3 21. In the given reaction, reagent [R] is : CH3 — CH2 — Br CH3 — CH2 — D [R] (a) Bu3SnD/In (b) LiAlD4 (c) Mg/ether followed by D2O (d) All of these 22. Methane and ethane both can be prepared in one step from which of the following compounds? (a) C2H4 (b) CH2O (c) CH Br 3 (d) CH3CH2OH 23. 2-chloro-3-methylbutane is treated with sodium in etherial solution, then it will give : (a) 2,4-dimethylhexane (b) 3,5-dimethylhexane (c) 2,3,4,5-tetramethylhexane (d) 2,6-dimethyloctane 24. CH3MgBr D2O (A), Product (A) of the reaction : (a) CH4 (b) CH3D (c) CH2D2 (d) CHD3 25. How many products will be formed in the given reaction ? (a) 1 (b) 2 (c) 3 (d) 4 164 Elementary Organic Chemistry for Medical → Na dry ether Cl OH Br 2 → Mg ether (A) C—O O