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प्रश्न
Which of the following compounds will undergo self-condensation in the presence of dilute NaOH solution?
पर्याय
C6H5CHO
CH3CH2CHO
(CH3)3C – CHO
H – CHO
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उत्तर
CH3CH2CHO
Explanation:
Aldehydes and ketones having at least one α-hydrogen undergo a reaction in the presence of dilute alkali as catalyst to form β-hydroxy aldehydes (aldol) or β-hydroxy ketones (ketol), respectively. This is known as Aldol reaction.
Because of the presence of α-hydrogen, CH3CH2CHO undergoes an aldol reaction.
APPEARS IN
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
How will you bring about the following conversion in not more than two steps?
Ethanol to 3-Hydroxybutanal
How will you bring about the following conversion in not more than two steps?
Benzaldehyde to 3-Phenylpropan-1-ol
Assertion: The α-hydrogen atom in carbonyl compounds is less acidic.
Reason: The anion formed after the loss of α-hydrogen atom is resonance stabilised.
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:
\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{....................}\\
\phantom{}\ce{2CH3 - C = O ->[Ba(OH)2] A ->[Δ] B + H2O}
\end{array}\]
Why is the α-hydrogens of aldehydes and ketones are acidic in nature?
Write a note on the aldol condensation reaction of acetaldehyde.
