Electrophilic addition to alkenes and Markovnikov rule

55 questions on Electrophilic addition to alkenes and Markovnikov rule from the Organic Reaction Mechanisms II: Electrophilic and Radical Reactions chapter: 11 NEET level, 22 JEE Main, 22 JEE Advanced. Each one opens with its answer and solution.

• Propene reacts with HBr in the absence of peroxide. The major product is NEET level
• Propene reacts with HBr in the presence of benzoyl peroxide. The major product is NEET level
• Which reagent sequence converts CH3-CH=CH2 mainly into propan-1-ol? NEET level
• Cyclohexene is treated with Br2 in CCl4. The product is NEET level
• Which carbocation is the most stable? NEET level
• The peroxide (Kharasch) effect is observed for the addition of which of the following to propene? NEET level
• But-1-ene is treated with Hg(OAc)2 in THF/H2O followed by NaBH4. The product is NEET level
• Ethene reacts with bromine water. The main organic product is NEET level
• Propene is hydrated with dilute H2SO4. The product is NEET level
• According to Markovnikov's rule, in the addition of HX to an unsymmetrical alkene, NEET level
• The intermediate formed in the first (slow) step of the addition of HBr to propene in the dark is NEET level
• 3,3-Dimethylbut-1-ene, (CH3)3C-CH=CH2, reacts with HBr (no peroxide). Count every distinct product formed through all carbocations that can arise from the initi... JEE Main level
• Consider the acyclic alkenes of molecular formula C5H10, with (E) and (Z) isomers counted separately (six alkenes: pent-1-ene, (E)-pent-2-ene, (Z)-pent-2-ene, 2... JEE Main level
• 3-Methylbut-1-ene, (CH3)2CH-CH=CH2, reacts with HBr in the absence of peroxide. The major product is JEE Main level
• 3,3-Dimethylbut-1-ene is heated with dilute aqueous H2SO4. The major alcohol is JEE Main level
• 1-Methylcyclohexene reacts with HBr in the dark. The major product is JEE Main level
• 1-Methylcyclohexene is treated with BH3.THF and then with H2O2/NaOH. The major product is JEE Main level
• Propene is treated with HCl in the presence of benzoyl peroxide. The major product is JEE Main level
• 2-Methylpropene, (CH3)2C=CH2, reacts with Br2 in water. The major product is JEE Main level
• 3-Methylbut-1-ene is treated with Hg(OAc)2 in water and then with NaBH4. The major product is JEE Main level
• The rates of addition of HBr (dark) to the alkenes follow the order JEE Main level
• Assertion (A): Addition of Br2 to cyclohexene gives trans-1,2-dibromocyclohexane. Reason (R): Br2 is non-polar and is polarised by the pi electrons of the alken... JEE Main level
• 2-Methylbut-2-ene, (CH3)2C=CH-CH3, reacts with HBr in the presence of peroxide. The major product is JEE Main level
• Styrene, C6H5-CH=CH2, reacts with HBr in the absence of peroxide. The major product is JEE Main level
• (E)-But-2-ene reacts with Br2 in CCl4. The product is JEE Main level
• 2-Methylpropene reacts with HBr in the presence of peroxide. The major product is JEE Main level
• But-1-ene is hydrated with dilute H2SO4. Which statement about the main product is correct? JEE Main level
• Propene reacts with HOCl (chlorine water). The major product is JEE Main level
• 3,3,3-Trifluoropropene, CF3-CH=CH2, reacts with HBr in the dark. The major product is JEE Main level
• Select the reactions that give the 1-bromo (terminal bromide) compound as the major product. JEE Main level
• Cyclopentene reacts with Br2 in CCl4. Select the correct statements. JEE Main level
• Which reagent combinations convert propene mainly into propan-2-ol? JEE Main level
• Select the correct statements about carbocation stability. JEE Main level
• 4-Methylpent-1-ene, (CH3)2CH-CH2-CH=CH2, reacts with HBr in the dark. Which is the major product? JEE Advanced level
• (CH3)3C-CH=CH2 reacts with HBr in the presence of peroxide. The major product is JEE Advanced level
• 3,3-Dimethylbut-1-ene is converted into an alcohol by three methods: (i) dilute H2SO4/water; (ii) Hg(OAc)2/H2O, then NaBH4; (iii) BH3.THF, then H2O2/NaOH. The m... JEE Advanced level
• (Z)-But-2-ene and (E)-but-2-ene are each treated separately with Br2 in water. Which statement about the 3-bromobutan-2-ol formed is correct? JEE Advanced level
• 1-Methylcyclohexene is treated with Br2 in methanol as the solvent. The major product is JEE Advanced level
• Which of the following alkenes does NOT give 2,3-dimethylbutan-2-ol as the major product on hydration with dilute H2SO4? JEE Advanced level
• 1,3-Butadiene reacts with one equivalent of HBr. Which pair correctly gives the major product at -80 degC and at +40 degC (after equilibration)? JEE Advanced level
• (E)-1-Phenylpropene, C6H5-CH=CH-CH3, is treated with HBr in the presence of peroxide. The major product is JEE Advanced level
• 2-Methylbut-2-ene is to be converted into 3-methylbutan-2-ol. Which sequence is suitable? JEE Advanced level
• Propene reacts with DBr in the presence of peroxide (D = deuterium). The major product is JEE Advanced level
• Methylenecyclobutane is treated with HBr in the dark. The major product is JEE Advanced level
• Assertion (A): Acid-catalysed hydration of 3,3-dimethylbut-1-ene gives mainly 3,3-dimethylbutan-2-ol. Reason (R): The initially formed secondary carbocation can... JEE Advanced level
• Assertion (A): Hydroboration-oxidation of an alkene gives the anti-Markovnikov alcohol without rearrangement. Reason (R): In the addition of B-H, boron adds to ... JEE Advanced level
• Match the reactions of propene (List I) with the major organic product (List II). List I: (P) HBr, no peroxide; (Q) HBr with peroxide; (R) BH3.THF, then H2O2/Na... JEE Advanced level
• Vinylcyclohexane, C6H11-CH=CH2, reacts with HCl (no peroxide). Taking the most stable carbocation reachable by a 1,2-shift, the major product is JEE Advanced level
• With HBr (no peroxide), which of the following alkenes give a major product that arises from a carbocation rearrangement? JEE Advanced level
• 1-Methylcyclohexene is treated with different reagents. For which reagents does the major product contain two stereocentres (formed as a racemate)? JEE Advanced level
• Select the correct statements about the peroxide-initiated addition of HBr to an alkene. JEE Advanced level
• Which of the following alkenes, on treatment with BH3.THF followed by H2O2/NaOH, give a mixture of two constitutionally isomeric alcohols in comparable amounts? JEE Advanced level
• Propene reacts with Br2 in water. Select the correct statements. JEE Advanced level
• Anti addition of Br2 in CCl4 is carried out on each alkene below. Select all alkenes that give a meso dibromide. JEE Advanced level
• 3-Methylbut-1-ene is converted into alcohols by various methods. Select the correct statements. JEE Advanced level