Free NEET Chemistry multiple-choice questions on Haloarenes. Attempt each question and reveal the answer with a full explanation.
Which of the following does NOT give a white precipitate with alcoholic silver nitrate? Chlorobenzene Benzyl chloride tert-Butyl chloride Allyl chloride Wurtz-Fittig reaction is used to prepare: Alkyl substituted benzene Biphenyl Alkanes Aryl fluorides The synthesis of Ar-I (Iodobenzene) from Benzene diazonium chloride is best achieved by treating the salt with: KI CuI/HI I 2 AgI Which of the following halides is practically inert to nucleophilic substitution under ordinary conditions due to the 'Double Bond Character' of the C-X bond? Vinyl chloride Allyl chloride Benzyl chloride Isopropyl chloride The reaction of Silver Benzoate with Br 2 in CCl 4 to form Bromobenzene is an example of: Hunsdiecker reaction Fittig reaction Wurtz-Fittig reaction Sandmeyer reaction Which of the following will not give a precipitate with alcoholic AgNO 3 even on prolonged heating? Chlorobenzene Benzyl chloride Allyl chloride tert-Butyl chloride The reaction of an aryl halide with an alkyl halide and sodium in dry ether is called: Wurtz-Fittig reaction Fittig reaction Wurtz reaction Ullmann reaction Which of the following sequence of reactions is suitable to synthesize chlorobenzene? Phenol, NaNO2 , HCl , CuCl Benzene, Cl2 , anhydrous FeCl3 The C-Cl bond in chlorobenzene is shorter than the C-Cl bond in CH 3Cl due to: sp 2 hybridization of carbon in C 6H 5Cl Resonance stabilization Inductive effect Both sp 2 hybridization and resonance What happens when chlorobenzene is treated with Na metal in dry ether? Diphenyl is formed Toluene is formed Benzene is formed Chlorobenzene does not react Among the following, the most reactive compound towards nucleophilic aromatic substitution is: 1-Chloro-2,4,6-trinitrobenzene 1-Chloro-2,4-dinitrobenzene p-Nitrochlorobenzene Chlorobenzene The reaction: ArN 2 + Cl - CuCl/HCl ArCl + N 2 is called: Sandmeyer reaction Gattermann reaction Finkelstein reaction Wurtz reaction Which of the following will not react with aqueous AgNO 3 even on heating? Chlorobenzene Allyl chloride Benzyl chloride t-Butyl chloride The reaction of Chlorobenzene with Mg metal in the presence of dry Tetrahydrofuran (THF) produces: Phenylmagnesium chloride Benzene Biphenyl Phenol Which reagent can be used to distinguish between Chlorobenzene and Benzyl chloride? Aqueous AgNO 3 followed by HNO 3 Beilstein test Lassaigne's test FeCl 3 solution Arrange the following compounds in increasing order of their reactivity towards nucleophilic aromatic substitution ( S N Ar ): (I) Chlorobenzene, (II) 4-nitrochlorobenzene, (III) 2,4-dinitrochlorobenzene, (IV) 2,4,6-trinitrochlorobenzene. I < II < III < IV IV < III < II < I I < III < II < IV II < I < III < IV The Meisenheimer complex is an intermediate formed during: Nucleophilic aromatic substitution Electrophilic aromatic substitution Free radical substitution Nucleophilic aliphatic substitution Which of the following is most reactive towards electrophilic substitution (Halogenation)? Toluene Benzene Chlorobenzene Nitrobenzene What is the product when chlorobenzene is heated with aqueous NaOH at 623 K and 300 atm pressure? Phenol Benzene Sodium benzoate Chlorophenol Aryl halides are less reactive than alkyl halides towards nucleophilic substitution due to: Resonance stabilization of C-X bond sp 2 hybridization of carbon attached to halogen Instability of phenyl cation All of the above Aryl halides are extremely less reactive towards nucleophilic substitution. However, the presence of which group at ortho and para positions increases their reactivity? -NO 2 -CH 3 -NH 2 -OCH 3 Which of the following compounds will not undergo Friedel-Crafts reaction? Chlorobenzene Toluene Nitrobenzene Xylene The reaction of chlorobenzene with CH 3Cl and sodium metal in dry ether to give toluene is known as: Wurtz-Fittig reaction Fittig reaction Wurtz reaction Friedel-Crafts reaction The treatment of chlorobenzene with CH 3COCl in the presence of anhydrous AlCl 3 gives: p-chloroacetophenone o-chloroacetophenone m-chloroacetophenone Both o- and p-chloroacetophenone Identify the compound which does NOT react with KOH to form an alcohol. Chlorobenzene Ethyl bromide Isopropyl chloride Benzyl chloride The conversion of chlorobenzene to phenol by heating with aqueous NaOH at 623 K and 300 atm is known as: Dow's Process Raschig Process Etard Reaction Stephen's Reduction Which of the following will undergo S N Ar (Nucleophilic Aromatic Substitution) most rapidly? 2,4,6-trinitrochlorobenzene 2,4-dinitrochlorobenzene 4-nitrochlorobenzene Chlorobenzene Which of the following reactions is used to distinguish between an alkyl halide and an aryl halide? Reaction with aqueous AgNO 3 Reaction with Na in dry ether Reaction with Mg in dry ether Reaction with KOH When 2,4,6-trinitrochlorobenzene is heated with water, it readily converts to picric acid. This exceptional reactivity toward nucleophilic aromatic substitution is primarily due to: Strong -I and -M effects of three -NO 2 groups at o - and p -positions. The formation of a stable benzyne intermediate. The high electronegativity of the chlorine atom. Strong +M effect of the -NO 2 groups. Although chlorobenzene is less reactive than benzene towards electrophilic substitution, the chlorine atom directs the incoming electrophile to: Ortho and Para positions due to its +M effect. Meta position due to its -I effect. Ortho position only due to steric factors. Any position as it does not affect orientation. Aryl halides are less reactive than alkyl halides towards nucleophilic substitution. Which of the following is NOT a reason for this? Greater stability of the aryl carbocation Resonance effect giving C-X bond partial double bond character Difference in hybridization of the carbon ( sp 2 vs sp 3 ) Repulsion between the nucleophile and the electron-rich benzene ring Which of the following statements regarding the Benzyne mechanism in nucleophilic aromatic substitution is correct? It involves an elimination-addition sequence. It involves an addition-elimination sequence. The intermediate contains a carbon-carbon triple bond in a six-membered ring. Substitution only occurs at the carbon atom originally bearing the leaving group. The stability of the Meisenheimer complex in nucleophilic aromatic substitution ( S N Ar ) is greatly enhanced by the presence of: Electron-withdrawing groups at ortho and para positions Electron-donating groups at ortho and para positions Alkyl groups at meta positions Large bulky groups at ortho positions The synthesis of fluorobenzene from benzene diazonium chloride and fluoroboric acid ( HBF 4 ) followed by heating is known as: Balz-Schiemann reaction Sandmeyer reaction Gattermann reaction Swarts reaction Among the following, the most reactive towards nucleophilic substitution ( S N Ar ) is: 1-fluoro-2,4-dinitrobenzene 1-chloro-2,4-dinitrobenzene 1-bromo-2,4-dinitrobenzene 1-iodo-2,4-dinitrobenzene The 'Ullmann Reaction' is used for the synthesis of biphenyls using which reagent? Copper powder Sodium metal Magnesium metal Zinc powder Which of the following compounds is the most reactive towards nucleophilic substitution with OH - ? 1-chloro-2,4-dinitrobenzene Chlorobenzene 4-nitrochlorobenzene 2,4,6-trinitrochlorobenzene Which of the following will react most slowly with aqueous AgNO 3 ? Chlorobenzene Benzyl chloride Ethyl chloride Allyl chloride Which of the following reagents is used in the Gattermann reaction for the preparation of chlorobenzene from benzene diazonium chloride? Cu / HCl CuCl / HCl Cu 2Cl 2 / HCl CuCl 2 / HCl Which of the following is most reactive towards nucleophilic aromatic substitution ( S N Ar )? 1-Chloro-2,4,6-trinitrobenzene 1-Chloro-4-nitrobenzene 1-Chloro-2,4-dinitrobenzene Chlorobenzene