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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

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.

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प्रश्न

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.

पर्याय

  • Assertion and reason both are correct and reason is correct explanation of assertion.

  • Assertion and reason both are wrong statements.

  • Assertion is correct statement but reason is wrong statement.

  • Assertion is wrong statement but reason is correct statement.

  • Assertion and reason both are correct statements but reasson is not correct explanation of assertion.

MCQ
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उत्तर

Assertion is wrong statement but reason is correct statement.

Explanation:

Because of the presence of electron-withdrawing carbonyl group, the alpha hydrogen atom in carbonyl compounds is acidic. In nature, hydrogen is very acidic.

Because the cation is released in the form of \[\ce{H-}\], the anion created after the loss of the -hydrogen atom is resonance stabilised. 

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पाठ 12: Aldehydes, Ketones and Carboxylic Acids - Multiple Choice Questions (Type - I) [पृष्ठ १७६]

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एनसीईआरटी एक्झांप्लर Chemistry Exemplar [English] Class 12
पाठ 12 Aldehydes, Ketones and Carboxylic Acids
Multiple Choice Questions (Type - I) | Q 44 | पृष्ठ १७६

संबंधित प्रश्‍न

A compound 'A' of molecular formula C2H3OCl undergoes a series of reactions as shown below. Write the structures of A, B, C and D in the following reactions :


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.

  1. Methanal
  2. 2-Methylpentanal
  3. Benzaldehyde
  4. Benzophenone
  5. Cyclohexanone
  6. 1-Phenylpropanone
  7. Phenylacetaldehyde
  8. Butan-1-ol
  9. 2, 2-Dimethylbutanal

How will you convert ethanal into the following compound?

But-2-enal


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?

Ethanol to 3-Hydroxybutanal


Describe the following:

Cross aldol condensation


Write a chemical equation for the following reaction: 
Propanone is treated with dilute Ba( OH)2.


What is substituted imine called?


Which product is formed when the compound  is treated with concentrated aqueous \[\ce{KOH}\] solution?


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) \[\begin{array}{cc}
\phantom{}\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - CHO}\phantom{..}\\
|\phantom{...}\\
\phantom{}\ce{CH3}\\
\end{array}\]


What product will be formed on reaction of propanal with 2-methylpropanal in the presence of \[\ce{NaOH}\]? What products will be formed? Write the name of the reaction also.


Which of the following gives aldol con~ensation reaction?


\[\ce{CH3-CH2-CHO ->[dil][alkali] Product}\]

The product in the above reaction is:


Why is the α-hydrogens of aldehydes and ketones are acidic in nature?


Assertion (A): The final product in Aldol condensation is always α, β-unsaturated carbonyl compound.

Reason (R): α, β-unsaturated carbonyl compounds are stabilised due to conjugation.


Identify A and B:


Write a note on the aldol condensation reaction of acetaldehyde.


Which one of the following undergoes reaction with 50% sodiumhydroxide solution to give the corresponding alcohol and acid:


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