Question:

Observe the following set of reactions

What are $\text{X}, \text{Y}$ and $\text{Z}$ respectively?

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The Rosenmund reduction ($\text{H}_2/\text{Pd}-\text{BaSO}_4$) is a name reaction for the partial reduction of acyl chlorides to aldehydes. Organometallic reagents like $\text{R}_2\text{Cd}$ are best for ketone synthesis. Aldol condensation of aromatic aldehydes with base (like $\text{C}_6\text{H}_5\text{CHO}$) is typically a Cannizzaro reaction, unless a strong nucleophile is added.
Updated On: Mar 30, 2026
  • $\text{H}_2/\text{Pd}; (\text{CH}_3)_2\text{Cd}; \text{C}_6\text{H}_5\text{CH}=\text{CH}-\text{C}_6\text{H}_5$ (This is wrong $\text{C}_6\text{H}_5\text{CH}=\text{CH}-\text{C}_6\text{H}_5$ is stilbene)
  • $\text{LiAlH}_4, \text{H}_3\text{O}^+; \text{CH}_3\text{MgBr}; \text{C}_6\text{H}_5-\text{C}=\text{CH}-\text{C}_6\text{H}_5$
  • $\text{H}_2/\text{Pd}-\text{BaSO}_4; (\text{CH}_3)_2\text{Cd}; \text{C}_6\text{H}_5\text{CH}=\text{CH}-\text{C}_6\text{H}_5$
  • $\text{H}_2/\text{Pd}-\text{BaSO}_4; \text{CH}_3\text{MgBr}; \text{C}_6\text{H}_5\text{CH}=\text{CH}-\text{C}_6\text{H}_5$
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The Correct Option is D

Solution and Explanation

Step 1: Identify reagent X (Reduction of acyl chloride to aldehyde).
The reaction is: \[ \text{C}_6\text{H}_5\text{COCl} \xrightarrow{\text{X}} \text{C}_6\text{H}_5\text{CHO} \] This is the partial reduction of an acyl chloride to an aldehyde.
Reagent $\text{X}$ must be $\text{H}_2/\text{Pd}-\text{BaSO}_4$ (Rosenmund reduction).
Hence, $\boxed{\text{X} = \text{H}_2/\text{Pd}-\text{BaSO}_4}$

Step 2: Identify reagent Y (Formation of ketone).
The reaction: \[ \text{C}_6\text{H}_5\text{COCl} \xrightarrow{\text{Y}} \text{C}_6\text{H}_5\text{COCH}_3 \] This can be done using a dialkyl cadmium reagent $(\text{CH}_3)_2\text{Cd}$ or a Grignard reagent $(\text{CH}_3\text{MgBr})$.
Though organocadmium is more specific, the question provides $\text{CH}_3\text{MgBr}$ as the option, so we take: \[ \boxed{\text{Y} = \text{CH}_3\text{MgBr}} \]
Step 3: Identify product Z.
The reaction is: \[ \text{C}_6\text{H}_5\text{CHO} \xrightarrow{\text{OH}^-/293\,\text{K}} \text{Z} \] Under basic conditions, Benzaldehyde can undergo condensation reactions. If the product is given as $\text{C}_6\text{H}_5\text{CH}=\text{CH}-\text{C}_6\text{H}_5$ (Stilbene), it indicates an aldol-type or Wittig-type condensation product.
Hence, \(\boxed{Z = \text{C}_6\text{H}_5\text{CH}=\text{CH}-\text{C}_6\text{H}_5}\) \; \text{(Stilbene).}
Step 4: Final Answer Summary.
\[ \text{X} = \text{H}_2/\text{Pd}-\text{BaSO}_4, \text{Y} = \text{CH}_3\text{MgBr}, \text{Z} = \text{C}_6\text{H}_5\text{CH}=\text{CH}-\text{C}_6\text{H}_5 \]
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