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प्रश्न
Why is the α-hydrogens of aldehydes and ketones are acidic in nature?
Account for the following:
The alpha (α)-hydrogens of aldehydes and ketones are acidic in nature.
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उत्तर
Because of the strong electron-withdrawing nature of the carbonyl groups and the resonance stabilisation of the conjugate base, aldehydes and ketones are acidic in nature.
| \[\begin{array}{cc} \ce{R}\phantom{..........}\\ \backslash\phantom{........}\\ \ce{C = O}\\ /\phantom{........}\\ \ce{H}\phantom{..........}\\ \end{array}\] |
\[\begin{array}{cc} \ce{R}\phantom{..........}\\ \backslash\phantom{........}\\ \ce{C = O}\\ /\phantom{........}\\ \ce{R}\phantom{..........}\\ \end{array}\] |
| Aldehyde | Ketone |
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संबंधित प्रश्न
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: 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.
Which of the following gives aldol con~ensation reaction?
Identify A and B from the following reaction:
\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{....................}\\
\phantom{}\ce{2CH3 - C = O ->[Ba(OH)2] A ->[Δ] B + H2O}
\end{array}\]
Convert the following:
Acetaldehyde to But-2-enal
The major product of the following reaction is:
Which of the following does not give aldol condensation reaction?
Identify A and B:
When acetaldehyde is treated with dilute NaOH, the following reaction is observed.
\[\begin{array}{cc}
\ce{2CH3 - CHO ->[dil.NaOH] CH3 - CH - CH2 - CHO}\\
\phantom{...............}|\\
\phantom{.................}\ce{OH}
\end{array}\]
- What are the functional groups in the product?
- Can another product be formed during the same reaction? (Deduce the answer by doing atomic audit of reactant and product).
- Is this an addition reaction or condensation reaction?
