JEE Challenger
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Identification of Chemical Properties and Isomeric Relationship of Product Y

Identify the correct statement with respect to the reaction product Y\mathbf{Y}:

Options

A

It gives a positive Tollens' test and is a functional isomer of X\mathbf{X}.

B

It gives a positive Tollens' test and is a geometrical isomer of X\mathbf{X}.

C

It gives a positive iodoform test and is a functional isomer of X\mathbf{X}.

Correct
D

It gives a positive iodoform test and is a geometrical isomer of X\mathbf{X}.

Step-by-Step Solution

To determine the correct statement regarding product Y\mathbf{Y}, let us analyze the nature of products X\mathbf{X} and Y\mathbf{Y}, their functional groups, and their chemical properties:

1. Functional Groups and Isomeric Relationship

  • Product X\mathbf{X} is an unsaturated ether (an alkoxyalkene) with the molecular formula C7H14O\mathrm{C}_7\mathrm{H}_{14}\mathrm{O}, containing an ether linkage (−O−-\mathrm{O}-) and an olefinic double bond (C=C\mathrm{C}=\mathrm{C}). Its degree of unsaturation (DU) is: DU=7+1−142=1\mathrm{DU} = 7 + 1 - \frac{14}{2} = 1
  • Product Y\mathbf{Y} has the same molecular formula C7H14O\mathrm{C}_7\mathrm{H}_{14}\mathrm{O} (DU=1\mathrm{DU} = 1), but possesses a ketone functional group, specifically a methyl ketone of the type: CH3−C∥O−R\mathrm{CH}_3-\overset{\mathrm{O}}{\overset{\parallel}{\mathrm{C}}}-\mathrm{R}
  • Since compounds X\mathbf{X} and Y\mathbf{Y} share the identical molecular formula (C7H14O\mathrm{C}_7\mathrm{H}_{14}\mathrm{O}) but have different functional groups (an ether-alkene vs. a carbonyl ketone), they are functional isomers of each other.
  • They are not geometrical isomers, as geometrical isomerism requires the same connectivity of atoms with different spatial orientations across a restricted rotation site (such as cis/trans alkenes).

2. Chemical Tests for Product Y\mathbf{Y}

  1. Tollens' Test:

    • Tollens' reagent ([Ag(NH3)2]+OH−\left[\mathrm{Ag}(\mathrm{NH}_3)_2\right]^+\mathrm{OH}^-) acts as a mild oxidizing agent that readily oxidizes aldehydes and α\alpha-hydroxy ketones to give a silver mirror.
    • Simple aliphatic ketones, such as Y\mathbf{Y}, are not oxidized by Tollens' reagent and therefore give a negative Tollens' test.
  2. Iodoform Test:

    • Compounds containing the methyl carbonyl moiety (CH3−C=O\mathrm{CH}_3-\mathrm{C}=\mathrm{O}) react with iodine in the presence of base (I2/NaOH\mathrm{I}_2 / \mathrm{NaOH}) to undergo haloform cleavage, producing a characteristic yellow precipitate of iodoform (CHI3\mathrm{CHI}_3): CH3−C∥O−R+3I2+4NaOH⟶R−C∥O−O−Na++CHI3↓+3NaI+3H2O\mathrm{CH}_3-\overset{\mathrm{O}}{\overset{\parallel}{\mathrm{C}}}-\mathrm{R} + 3\mathrm{I}_2 + 4\mathrm{NaOH} \longrightarrow \mathrm{R}-\overset{\mathrm{O}}{\overset{\parallel}{\mathrm{C}}}-\mathrm{O}^-\mathrm{Na}^+ + \mathrm{CHI}_3\downarrow + 3\mathrm{NaI} + 3\mathrm{H}_2\mathrm{O}
    • Because Y\mathbf{Y} contains the CH3−CO−\mathrm{CH}_3-\mathrm{CO}- group, it gives a positive iodoform test.

Conclusion:

Product Y\mathbf{Y} gives a positive iodoform test and is a functional isomer of X\mathbf{X}.

Therefore, the correct statement is given by option (C).