Time Limit 60 Minutes 90 Marks

Q1. 2-Methylbutane can be obtained by catalytic hydrogenation of how many constitutional isomeric alkenes ? (a) 1 (b) 2 (c) 3 (d) 4 Q2. Which one is ambiguous name ? (a) Pentane (b) Neopentane (c) sec-Butanol (d) sec-Pentanol Q3. The correct order for increasing heat of combustion of the three hydrocarbons should be

(a) I < II < III (b) III < I < II (c) III < I < II (d) III < I < II Q4. The total number of isomeric cyclic compounds of the molecular formula C5H10 having no dobule bond can be (a) 3 (b) 4 (c) 5 (d) 6 Q5. The maximum possible number of constitutional isomeric alkene (C6H10) that can be hydrogenated by catalytic

hydrogenation to methylcyclopentane is (a) 3 (b) 4 (c) 5 (d) 6 Q6. The potential energy diagram for rotation of the C2 C3 bond of butane through 360, starting with the least stable

conformer is drawn below.

The most stable conformer is obtained by rotation through a dihedral angle of (a) 60 (b) 120 (c) 180 (d) 360 Q7. Which of the following three alkenes is most stable ?

(a) I (b) II (c) III (d) All are equal stable Q8. The above three alkenes are hydrogenated to form alkenes Ia, IIa and IIIa respectively. Which of the alkane you

expect to be most stable ? (a) Ia (b) IIa (c) IIIa (d) All are equal Q9. Methylcyclohexane can be prepared by the catalyte hyroenation of hou many isomeric alkenes ? (a) 1 (b) 2 (c) 3 (d) 4 Q10. The cis-and tans-2, 3-dichloro-2-butenes have different boiling points because the two isomers have (a) different dipole-dipole interactions (b) different van der walls interactions (c) both (a) and (b) (d) difference in H-bonding

Q11. CH3CH = CHCH2

Br|CH CH2CH3 3CH OH CH3CH = CHCH = CHCH2CH3

which of the statement is true regarding above reaction ? (a) It is an example of E2 reaction (b) It is an example of E1 reaction and involves the formation of 2 allylic carbocation (d) The reaction should be substitution

I II III

0 60 120 180 240 300 360

Potential energy

I II III

Q12. NBS is used for brominating allylic carbon atom. Predict the product in the following reaction

(a) (b) (c) Both (a) and (b) (d) Q13. Allylic substitution in CH3CH = CH2 may be carried out by (a) Sulphuryl chloride, SO2Cl2 (b) tert-butyl hypochlorite, Me3COCl (c) NBS (d) All the three Q14. BrCH2CHBrCH3 alc. KOH( HBr) Major product is

(a) CH2 = CBrCH3 (b) CH2 = CHCH2Br (c) BrCH = CHCH3 (d) All the three in equivalent amount

Q15. The maximum number of possible products formed in the following reaction is

(a) 2 (b) 3 (c) 4 (d) 5

Q16. The correct IUPAC name for is (a) 1, 5-dimethylcyclohexene (b) 1, 4-dimethylcyclohexene (c) both are equally correct (d) m-Dimethylcyclohexene

Q17. An organic compound (C6H12) decolorizes Br2 and is oxidised by hot acidified KMnO4 to a resolvable carboxylic acid,

C4H9COOH. The compound is

(a)

3 3

2 2 3

CH CH| |

CH C CHCH CH (b)

3

2 2 2 3

CH|

CH C CH CH CH (c) 2 2 3

3

CH CHCHCH CH|CH

(d) CH2 = CHCH2CH(CH3)2

Q18. Which of the following cant be detected by bromine in carbon tetrachloride ? (a) Cyclohexene (b) 1, 3-Cyclohexadiene (c) Tetrachloroethene (d) None of the three Q19. Propene (I), 2-methylpropene (II), and ethene (III), each containing one carbon-carbon double bond, is separately

treated with HI under the same set of conditions. The order of reactivity for the three alkenes should be (a) I > II > III (b) III > II > I (c) II > I > III (d) I = II = III

Q20. can best be prepared by which sequence of reaction

(a) CH3CH2C CH + NaNH2 [ ] (b) + NaNH2 [ ] 3 2CH CH Br

(c) (d) All the three Q21. 4, 4-Dimethyl-2-pentyne can be synthesised by using CH3C = CH Me3CBr Me3CC = CH CH3I I II III IV (a) Combination of I and II in presence of NaNH2 (b) Combination of III and IV in presence of NaNH2 (c) either of the two (d) None of the two

CH2CHBrCH2CH3

2 5

2 5

C H ONaC H OH

C = CHBr

C = CCH2CH2

Br

CH3

Br

CH3

+ C2H5OH heat

Br

Br

CH2Br

Br

2 2

NBS, heatCH Cl

Q22. Arrange the following compounds in decreasing order of reactivity with Br2 CH2 = CH2 (I), CH = CH (II), CH2 = CHCl (III) (a) II > III > I (b) II > I > III (c) I > II > III (d) All are equal Q23. Which reagent should be used for getting the following transformation in quantitative yield ?

3 3 2

O||

CH C C H CH CH C H

(a) Hg2+ / H2SO4 (b) BH2 THF; H2O2/OH (c) Sia2BH. THF; H2O/OH- (d) Conversion not possible in a direct reaction

Q24. Predict the major product in the following reaction : CH2 = CH C CH 1 HBr Product (a) CH3CH(Br)C CH (b) CH2 = CH C(Br) = CH2 (c) Both (d) CH2 = CH CH2 = CHBr Q25. Which of the following statements is true regarding the stability of following three dienes ? CH2 = CH CH = CH2 CH2 = CH CH2 CH = CH2 CH2 = C = CH CH3 (a) 1, 3-Butadiene is (a conjugated diene) is more stable than 1, 4-pentadiene (an isolated) due to resonance.

(b) 1, 3-Butadiene is more stale than 1, 4-pentadiene becaue the former has a strong carbon-carbon single bond; while the latter has, two weaker carbon-carbon single bonds

(c) 1, 2-Butadiene is less table than 1, 3-butadiene because the former has sp hybridised carbon atom (d) All the three Q26. Which of the dihydroxybutane can be converted casily into 1, 3-butadiene ? (a) CH3CH(OH)CH(OH)CH3 (b) HOCH2CH2CH2CH2OH (c) HOCH2CH2CH(OH)CH2OH (d) Both (b) and (c) Q27. Butadiene is treated with 1 equivalent of HBr at 80C, the major product will be (a) BrCH2CH = CHCH3 (b) CH3CHBrCH = CH2 (c) Both (d) Reaction not possible Q28. CH2 = CH CH = CH2 + HBr (1 eq.) peroxide Product is (a) CH3CH = CHCH2Br (b) CH3CHBrCH = CH2 (c) Both (a) and (b) (d) No reaction Q29. 1-Methyl-1, 3-cyclohexadiene + H2S (1 eq. ) peroxide Prodcut is

(a) (b) (c) (d) No reaction Q30. Which of the following does not involve the formation of an allylic carbocation ? (a) 1, 3-Butadiene + Br2 (b) 1-Chloro-2-butene + aq. AgNO3 (c) 3-Chloro-1-methylcyclopentene (d) None of the three