Preparation of alkyl and aryl halides

37 questions on Preparation of alkyl and aryl halides from the Haloalkanes and Haloarenes chapter: 8 NEET level, 14 JEE Main, 15 JEE Advanced. Each one opens with its answer and solution.

• Which reagent converts ethanol into chloroethane so that both by-products are gases, making purification easy? NEET level
• Propene reacts with HBr in the presence of an organic peroxide. The major product is NEET level
• In the Finkelstein reaction CH3CH2Cl is converted into CH3CH2I using NaI in dry acetone. The reaction goes to completion because NEET level
• Benzenediazonium chloride is converted into fluorobenzene by treating it with NEET level
• 2-Methylbutane is subjected to free-radical monochlorination (Cl2, light). Counting all structurally different monochloro products and counting each pair of ena... JEE Main level
• Propane undergoes free-radical monochlorination at 300 K. Take the relative reactivity per hydrogen as primary : secondary = 1 : 3.8. The percentage of 2-chloro... JEE Main level
• Which alcohol gives turbidity immediately (within seconds) at room temperature with Lucas reagent (conc. HCl and anhydrous ZnCl2)? JEE Main level
• Direct iodination of benzene with I2 alone is reversible and gives little iodobenzene, but the reaction proceeds when a little HNO3 is added. The role of HNO3 i... JEE Main level
• Which of the following alkanes gives only one monochlorination product (constitutional isomers considered; stereoisomers ignored)? JEE Main level
• Silver propanoate is refluxed with bromine in CCl4 (Hunsdiecker reaction). The organic product is JEE Main level
• Which of the following correctly describe the reactions of N-bromosuccinimide (NBS) with light or peroxide in CCl4? JEE Main level
• 4-Methylaniline is diazotised with NaNO2 and HCl at 273-278 K to give 4-methylbenzenediazonium chloride. Which of the following transformations of this salt are... JEE Advanced level
• 3-Methylbut-1-ene is treated with HBr in the absence of peroxide. The major product is JEE Advanced level
• 2-Methylbutane undergoes free-radical monochlorination. Take relative reactivity per hydrogen as primary : secondary : tertiary = 1 : 4 : 5. The percentage of 2... JEE Advanced level
• Aniline is diazotised (NaNO2, HCl, 273 K), the product is heated with CuBr and HBr, the resulting compound is converted to its Grignard reagent with Mg in dry e... JEE Advanced level
• Propene is heated with Cl2 at 773 K to give compound P. P is then treated with HBr in the presence of a peroxide. The major final product is JEE Advanced level
• 2-Methylpropene is treated with HBr under two sets of conditions. Which statements are correct? JEE Advanced level
• Toluene (9.2 g, molar mass 92 g/mol) is chlorinated with Cl2 and FeCl3 so that all of it is consumed. The ring monochlorination products (only ortho and para is... JEE Advanced level
• 1-Phenylprop-1-ene, C6H5-CH=CH-CH3, is treated with HBr in the absence of peroxide. The major product is JEE Advanced level
• Which of the following alcohols gives turbidity almost immediately at room temperature with Lucas reagent (anhydrous ZnCl2 in conc. HCl)? NEET level
• Conversion of an alcohol R-OH into R-Cl is best carried out with SOCl2 because NEET level
• In the Finkelstein reaction, CH3CH2Br + NaI ->[dry acetone] CH3CH2I + NaBr proceeds to completion mainly because NEET level
• Propene reacts with HBr in the presence of an organic peroxide. The major product is NEET level
• Cyclohexene is treated with N-bromosuccinimide (NBS) in CCl4 in the presence of light with a trace of peroxide. The main product is JEE Main level
• Fluorobenzene can be prepared from aniline by diazotisation followed by JEE Main level
• Toluene is converted to C6H5CH2Cl and to a mixture of o-ClC6H4CH3 and p-ClC6H4CH3 under two different sets of conditions. The correct pairing is JEE Main level
• Direct iodination of benzene with I2 alone gives very poor yields of iodobenzene, but the yield is good when a little conc. HNO3 is added. The role of HNO3 is t... JEE Main level
• Silver propanoate is heated with bromine in CCl4 (Borodin-Hunsdiecker reaction). The organic product is JEE Main level
• Propan-1-ol is converted into 1-bromopropane with PBr3. The balanced equation shows that JEE Main level
• (R)-Butan-2-ol is treated with SOCl2 in the presence of pyridine. Pyridine ensures that the reaction proceeds by an S_N2 pathway with inversion at the stereocen... JEE Main level
• 2-Methylbutane, CH3-CH(CH3)-CH2-CH3, undergoes monochlorination with Cl2 under light. Assume the relative reactivity per hydrogen is primary : secondary : terti... JEE Advanced level
• Which of the following statements about the conversion of alcohols into alkyl halides are correct? JEE Advanced level
• 3-Methylbut-1-ene reacts with HBr in the absence of peroxide. Which statements are correct? JEE Advanced level
• Propene is treated with HBr in the presence of peroxide to give A. A is heated with KCN in ethanol to give B, and B is heated with aqueous H3O+ to give C. The c... JEE Advanced level
• The best two-step route to 1-chloro-3-nitrobenzene starting from benzene is JEE Advanced level
• Which of the following reactions give the stated aryl halide as the principal product? JEE Advanced level
• In the free radical monohalogenation of 2-methylpropane at one hydrogen of each kind, the relative reactivity per hydrogen (tertiary : primary) is 5 : 1 for chl... JEE Advanced level