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Karnataka Board PUCPUC Science 2nd PUC Class 12

Through which of the following reactions number of carbon atoms can be increased in the chain? (i) Grignard reaction (ii) Cannizaro’s reaction (iii) Aldol condensation (iv) HVZ reaction

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Question

Through which of the following reactions number of carbon atoms can be increased in the chain?

(i) Grignard reaction

(ii) Cannizaro’s reaction

(iii) Aldol condensation

(iv) HVZ reaction

Short/Brief Note
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Solution

(i) Grignard reaction

(iii) Aldol condensation

Explanation:

Grignard reagent is used to add number of carbon atom in chain.

\[\begin{array}{cc}
\phantom{....................}\ce{R'}\\
\phantom{...................}|\\
\ce{RCHO + R'MgX ->[H2O] R - CH - OH}
\end{array}\]

Aldol condensation involves condensation of aldehydes and ketones with α-hydrogen.

\[\begin{array}{cc}
\ce{CH3CHO ->[dil NaOH] CH3CHCH2CHO ->[Δ][-H2O] CH3CH = CHCHO}\\
|\phantom{..............}\\
\ce{\underset{Aldol}{OH}\phantom{............}}\\
\end{array}\]

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Chapter 12: Aldehydes, Ketones and Carboxylic Acids - Multiple Choice Questions (Type - I) [Page 171]

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NCERT Exemplar Chemistry Exemplar [English] Class 12
Chapter 12 Aldehydes, Ketones and Carboxylic Acids
Multiple Choice Questions (Type - I) | Q 16 | Page 171

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