Please answer questions 47-50 The electrophilic bromination or chlorination of b
ID: 992815 • Letter: P
Question
Please answer questions 47-50 The electrophilic bromination or chlorination of benzene requires, in addition to the halogen: a hydroxide ion. a Lewis base. a Lewis acid. peroxide. Aryl and vinyl halides cannot be used in the Friedel-Crafts alkylation because they do not form carbocautions readily. True False Which is not a characteristic of aromatic compounds? Aromatic compounds are non-cyclic. Aromatic compounds are conjugated. Aromatic compounds meet the Huckel's rule. Aromatic compounds are planar. Which of the compounds below is a product of this reaction? 1-chlorobenzene 1, 2, dichlorobenzene 2,3 dibromobenzene 1,4-cyclohexadieneExplanation / Answer
47) c. A Lewis acid
Electrophilic halogenation generally occurs when we take the halogen gas, X2 (X= Cl/ Br) with a catalys Lewis acid like AlCl3 or FeCl3. These mild acids help in increasing the electrophilicity of the halogen molecule by forming a complex with it (For example: AlCl3 + Cl2 --> Cl+ + AlCl4- ; this Cl+ then acts as an efficient electrophile for substitution)
48) a. True
Aryl/ Vinyl carbocations are too unstable and not formed easily. Thus, they cannot react in a Friedel- Crafts reaction.
49) a. Aromatic compounds are non cyclic.
By definition, aromaticity is applicable to cyclic compounds with conjugated, planar multiple bonds. They are never non-cyclic.
50) a. 1-chlorobenzene
Reaction with a halogen in the presene of FeCl3 leads to monosubstitution on the benzene ring.