Chemistry Q66 – JEE-MAIN 2026

Home Chemistry Organic Chemistry – Some Basic Principles and TechniquesQuestion #461

Given below are two statements: Statement I: 3-phenylpropene reacts with HBr and gives secondary alkyl bromide having a chiral carbon atom as the major product. Statement II: Aryl chlorides and aryl cyanides can be prepared by Sandmeyer reaction as well as Gattermann reaction. In the light of the above statements, choose the correct answer from the options given below

Clue 1 of 3: Reaction Mechanisms and Stereochemistry

Analyze the electrophilic addition of HBr to an alkene, considering carbocation stability and the conditions for chirality. Also, recall the specific reagents and products for named reactions involving diazonium salts.

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Ninja Strategy•Evaluate Each Statement Independently

Determine the truth value of each statement separately. Statement I involves Markovnikov addition and chirality, while Statement II tests knowledge of Sandmeyer and Gattermann reactions. Combine the truth values to find the correct option.

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Step 1: Analyze Statement I (Electrophilic Addition and Chirality)✦ Active

3-phenylpropene ( $C_{6} H_{5} - C H_{2} - C H = C H_{2}$ ) reacts with HBr via electrophilic addition. Protonation occurs at the terminal carbon ( $C_{1}$ ) to form the more stable secondary carbocation at $C_{2}$ ( $C_{6} H_{5} - C H_{2} - \overset{+}{C} H - C H_{3}$ ), which is stabilized by resonance with the phenyl group. Subsequent attack by $B r^{-}$ yields 2-bromo-1-phenylpropane ( $C_{6} H_{5} - C H_{2} - C H (B r) - C H_{3}$ ). The carbon at $C_{2}$ is bonded to four different groups ( $- H$ , $- B r$ , $- C H_{3}$ , $- C H_{2} - C_{6} H_{5}$ ), making it a chiral center. Thus, Statement I is TRUE.

Step 2: Analyze Statement II (Sandmeyer and Gattermann Reactions)○ Expand

The Sandmeyer reaction converts aryl diazonium salts to aryl chlorides ( $A r - C l$ ), aryl bromides ( $A r - B r$ ), and aryl cyanides ( $A r - C N$ ) using $C u C l / H C l$ , $C u B r / H B r$ , and $C u C N / K C N$ respectively. The Gattermann reaction converts aryl diazonium salts to aryl chlorides ( $A r - C l$ ) and aryl bromides ( $A r - B r$ ) using copper powder and $H C l$ or $H B r$ . However, the Gattermann reaction does not produce aryl cyanides. Therefore, Statement II is FALSE.

Step 3: Conclude based on statement validity○ Expand

Statement I is true, and Statement II is false. This corresponds to option 3.

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Chemistry Question 66 – JEE-MAIN 2026

Clue 1 of 3: Reaction Mechanisms and Stereochemistry

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