BENZENE AND HALOALKANES

Which of the following statements about benzene is true?

• Six 2p orbitals overlap to form three delocalized л bonds.

• All carbon atoms are sp-hybridised.

• Benzene undergoes addition reaction.

• Molecular formula of benzene is C₆H₅.

• Friedel-Crafts acylation

• Hoffman’s Degradation

• Coupling reaction

• Friedel-Crafts alkylation

Which of the following compounds does not decolourise reddish brown of bromine with the present of ultraviolet light?

• Toluene

• Benzene

• Cyclohexene

• 1,2-dimethylbenzene

• Phenol

• Nitrobenzene

• Methylbenzene

• Phenylmethanol

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The main reaction of haloakanes is

• Free radical substitution

• Electrophilic substitution

• Condensation

• Nucleophilic substitution

Iodoethane reacts with hydroxide ion, through S_N2 mechanism. What is the effects by doubling the concentration of OH^- and decreasing the concentration of iodoethane by factor of 2?

• The rate of reaction is doubled

• The rate of reaction remain the same

• The rate of reaction is quadrupled

• The rate of reaction decrease by factor of 2

Which one of the following would you expect to have the highest boiling point?

• CH₃CH₂CH(CH₃)CH₃

• CH₃CH₂CH₂CH₂Cl

• CH₃CH₂CH₂CH₂OH

• CH₃CH₂-O-CH₂CH₃

Haloalkanes can be synthesis directly from

• Alcohols

• Amines

• Benzene

• Aldehydes

Which of the following methods can be used to make alcohols?

i. Electrophilic addition of water to an alkene in the presence of an acid catalyst

ii. Boiling a haloalkane with aqueous sodium hydroxide under reflux

iii. Passing carbon dioxide through a solution of a Grignard reagent

• i only

• i and ii

• ii and iii

• i, ii and iii