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प्रश्न
Which of the following does not give aldol condensation reaction?
विकल्प
CH3 – CHO
CH3COCH3
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उत्तर
Explanation:
Aldehydes and ketones with at least one α-hydrogen undergo a reaction in the presence of dilute alkali as a catalyst to create β-hydroxy aldehydes (aldol) or β-hydroxy ketones (ketol), respectively. This is known as an Aldol reaction.
Due to the lack of α-hydrogen, benzaldehyde does not undergo aldol reaction.
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संबंधित प्रश्न
Write the products formed when CH3CHO reacts with the following reagents: CH3CHO in the presence of dilute NaOH
Which of the following compounds would undergo aldol condensation, which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.
- Methanal
- 2-Methylpentanal
- Benzaldehyde
- Benzophenone
- Cyclohexanone
- 1-Phenylpropanone
- Phenylacetaldehyde
- Butan-1-ol
- 2, 2-Dimethylbutanal
Write structural formulas and names of four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde acts as nucleophile and which as electrophile.
How will you bring about the following conversion in not more than two steps?
Benzaldehyde to 3-Phenylpropan-1-ol
Why is alpha (α) hydrogen of carbonyl compounds acidic in nature?
Which of the following compounds do not undergo aldol condensation?
(i) \[\ce{CH3 - CHO}\]
(ii) 
(iii) \[\begin{array}{cc}
\phantom{}\ce{O}\\
\phantom{}||\\
\ce{CH3 - C - CH3}
\end{array}\]
(iv) \[\begin{array}{cc}
\phantom{}\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - CHO}\phantom{..}\\
|\phantom{...}\\
\phantom{}\ce{CH3}\\
\end{array}\]
Assertion: Aromatic aldehydes and formaldehyde undergo Cannizaro reaction.
Reason: Aromatic aldehydes are almost as reactive as formaldehyde.
Give reasons to support the answer:
Presence of Alpha hydrogen in aldehydes and ketones is essential for aldol condensation.
Identify A and B from the following reaction:
\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{....................}\\
\phantom{}\ce{2CH3 - C = O ->[Ba(OH)2] A ->[Δ] B + H2O}
\end{array}\]
Predict the reagent for carrying out the following transformations:
Ethanal to 3-hydroxy butanal
