Match the observation in List I with the compound in List II. List I: (P) silver mirror with Tollens reagent and no yellow precipitate with NaOH/I2; (Q) yellow precipitate with NaOH/I2 but no silver mirror; (R) white precipitate with ammoniacal AgNO3; (S) violet colour with neutral FeCl3. List II: (1) phenol; (2) propyne; (3) butan-2-one; (4) methanal.

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JEE Advanced levelSingle correct optionDifficulty 3 of 3si050

Match the observation in List I with the compound in List II. List I: (P) silver mirror with Tollens reagent and no yellow precipitate with $NaOH / I X_{2}$ ; (Q) yellow precipitate with $NaOH / I X_{2}$ but no silver mirror; (R) white precipitate with ammoniacal $AgNO X_{3}$ ; (S) violet colour with neutral $FeCl X_{3}$ . List II: (1) phenol; (2) propyne; (3) butan-2-one; (4) methanal.

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

Answer: B

Methanal reduces Tollens reagent but has no

CH X_{3} CO X^{-}

, so P matches 4. Butan-2-one is a methyl ketone (iodoform positive, Tollens negative), so Q matches 3. Propyne is a terminal alkyne, so R matches 2, and phenol gives the violet complex, so S matches 1.

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Answer: B

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