Match each reaction in Column I with the key intermediate in Column II. Column I: (P) 1-fluoro-4-nitrobenzene + CH3ONa; (Q) chlorobenzene + KNH2 in liquid NH3; (R) anisole + HI; (S) (CH3)3C-O-C2H5 + HI. Column II: (1) benzyne; (2) Meisenheimer complex; (3) alkyl aryl oxonium ion attacked at CH3 by iodide, no carbocation; (4) tertiary carbocation.

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Match each reaction in Column I with the key intermediate in Column II. Column I: (P) 1-fluoro-4-nitrobenzene + $CH X_{3} ONa$ ; (Q) chlorobenzene + $KNH X_{2}$ in liquid $NH X_{3}$ ; (R) anisole + HI; (S) $(CH X_{3}) X_{3} C - O - C X_{2} H X_{5}$ + HI. Column II: (1) benzyne; (2) Meisenheimer complex; (3) alkyl aryl oxonium ion attacked at $CH X_{3}$ by iodide, no carbocation; (4) tertiary carbocation.

AP-2, Q-1, R-3, S-4
BP-1, Q-2, R-3, S-4
CP-2, Q-1, R-4, S-3
DP-3, Q-1, R-2, S-4

Answer: A

P is an activated aryl fluoride and reacts by addition-elimination through a Meisenheimer complex. Q has no activating group, so a strong base causes elimination-addition through benzyne. R cleaves by SN2 attack of iodide on the methyl carbon of the aryl methyl oxonium ion, while S ionises to the tertiary carbocation (SN1). The match is P-2, Q-1, R-3, S-4.

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