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 Multiple Choice QuestionsMultiple Choice Questions

181.

The carbon-carbon bond length in benzene is

  • in between C2H6 and C2H4

  • same as in C2H4

  • in between  C2H6 and C2H2

  • in between C2H4 and C2H2


182.

Which one of these is not true for benzene?

  • It forms only one type of monosubstituted product

  • There are three carbon-carbon single bonds and three carbon-carbon double bonds

  • The heat of hydrogenation of benzene is less than the theoretical value

  • The bond angle between the carbon-carbon bonds is 120°


183.

Which one of the following conformations of cyclohexane is the least stable?

  • Half-chair

  • Boat

  • Twisted-boat

  • Chair


184.

Which one of these is not true for benzene?

  • It forms only one type of monosubstituted product

  • There are three carbon-carbon single bonds and three carbon-carbon double bonds

  • Heat of hydrogenation of benzene is less than its theoretical value

  • The bond angle between carbon-carbon bonds is 120°


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185.

A dibromo derivative of an alkane reacts with sodium metal to form an alicyclic hydrocarbon. The derivative is

  • 1, 1-dibromopropane

  • 2, 2-dibromobutane

  • 1, 2-dibromoethane

  • 1, 4-dibromobutane


D.

1, 4-dibromobutane

ω-dihalides when reacts with sodium metal, gives cyclic hydrocarbons. This is an example of intramolecular Wurtz reaction.

            


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186.

Which one of the following is an intermediate in the reaction of benzene with CH3Cl in the presence of anhydrous AlCl3?

  • Cl-

  • CH3-

  • CH3+


187.

Cycloalkane formed when 1,4-dibromopentaneis heated with sodium is

  • methyl cyclobutane

  • cyclopentane

  • cyclobutane

  • methyl cyclopentane


188.

Methane can be converted into ethane by the reactions

  • chlorination followed by the reaction with alcoholic KOH

  • chlorination followed by the reaction with aqueous KOH

  • chlorination followed by Wurtz reaction

  • chlorination followed by decarboxylation


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189.

Least energetic conformation of cyclohexane is

  • chair conformation

  • boat conformation

  • cis conformation

  • E-Z form


190.

An alkyl bromide (X) reacts with sodium in ether to form 4,5-dIethyl octane, the compound X is

  • CH3(CH2)3Br

  • CH3(CH2)5Br

  • CH3(CH2)3CH(Br)CH3

  • CH3—(CH2)2—CH(Br)—CH2—CH3


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