Question

The reaction(s) that give(s) tert-butylbenzene as the major product is/are

• A. A
• B. B
• C. C
• D. D

Hint:

Friedel–Crafts alkylation depends on stability of carbocationTertiary carbocations give tert-alkylbenzene as product

Answer 1

The Correct Option is A, C

Step 1: Understand formation of tert-butylbenzene.
tert-Butylbenzene is formed via Friedel–Crafts alkylation involving tert-butyl carbocation ($(CH_3)_3C^+$)Thus, reactions generating this carbocation will give the desired product

Step 2: Analyze option (A).
tert-Butyl chloride with anhydrous AlCl$_3$ forms tert-butyl carbocation
\[ (CH_3)_3CCl \xrightarrow{AlCl_3} (CH_3)_3C^+ \]
This reacts with benzene to give tert-butylbenzeneThus, option (A) is correct

Step 3: Analyze option (B).
Isopropyl chloride forms secondary carbocation ($(CH_3)_2CH^+$)This leads to isopropylbenzene (cumene), not tert-butylbenzeneThus, (B) is incorrect

Step 4: Analyze option (C).
Isobutylene in presence of strong acid (H$_2$SO$_4$) forms tert-butyl carbocation via protonation and rearrangement
\[ (CH_3)_2C=CH_2 \xrightarrow{H^+} (CH_3)_3C^+ \]
This reacts with benzene to give tert-butylbenzeneThus, option (C) is correct

Step 5: Analyze option (D).
Bromobenzene with Mg forms phenyl magnesium bromide (Grignard reagent)This reacts with tert-butyl chloride to give substitution products, not Friedel–Crafts alkylationThus, tert-butylbenzene is not formed

Step 6: Identify correct reactions.
Only those reactions that generate tert-butyl carbocation will give tert-butylbenzene

Step 7: Conclusion.
\[ \boxed{\text{(A) and (C)}} \]