323461
Which statement about the aldol condensation is correct?
1 A Lewis acid is commonly used as a catalyst
2 The initial step is probably the formation of a carbanion.
3 A Lewis base is employed to induce carbocation formation
4 The carbon chain is lengthened throuh the elimination of 1 mole of \(\mathrm{H}_{2} \mathrm{O}\)
Explanation:
Conceptual Questions
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323462
Which of the following is the incorrect statement?
1 \({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can give aldol condensation.
2 When mixture of ethanal and propanal is treated with aq. NaOH , structurally four different aldols are formed.
3 Mixture of HCHO and PhCHO cannot give aldol condensation product.
4 Aldol reaction is possible even if one of the carbonyl compounds contains an \({\mathrm{\alpha-}}\) hydrogen.
Explanation:
\({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can't give aldol condensation as it dosen't have \({\mathrm{\alpha}}\)-Hydrogen. Under the same conditions it gives \({\mathrm{\mathrm{CHCl}_{3}}}\) and \({\mathrm{\mathrm{HCOO}^{-}}}\).
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323463
On treatment of propanone with dilute \(\mathrm{Ba}(\mathrm{OH})_{2}\), the product formed is
1 aldol
2 phorone
3 propionaldehyde
4 4-hydroxy-4-methyl-2-pentanone.
Explanation:
In the presence of \(\mathrm{Ba}(\mathrm{OH})_{2^{\prime}}\) propanone (acetone) undergoes aldol condensation as :
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323464
Assertion : 2 - Butenal lacks enolisable \(\mathrm{H}\) atom, \(\alpha\) to carbonyl group, still it has sufficient acidic character. Reason : The conjugate base of 2 - butenal is stabilised by resonance.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
2 - Butenal contains \(\gamma-\mathrm{H}-\) atoms and the conjugate base obtained after the removal of \(\gamma-\mathrm{H}-\) atom, is stabilised by resonance. Hence, 2 - Butenal is sufficiently acidic. However, it lacks enolisable \(\mathrm{H}\)-atom, \(\alpha\) to carbonyl group.
AIIMS - 2009
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323465
Assertion : Acetaldehyde undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Reason : Aldehydes which do not contain \(\alpha\) hydrogen undergo aldol condensation.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Acetaldehyde which has \(\alpha\)-hydrogen undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Aldehydes lacking \(\alpha\) - hydrogens undergo Cannizzaro reaction, involving self oxidation and reduction upon heating with concentrated alkali. So the option (3) is correct.
323461
Which statement about the aldol condensation is correct?
1 A Lewis acid is commonly used as a catalyst
2 The initial step is probably the formation of a carbanion.
3 A Lewis base is employed to induce carbocation formation
4 The carbon chain is lengthened throuh the elimination of 1 mole of \(\mathrm{H}_{2} \mathrm{O}\)
Explanation:
Conceptual Questions
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323462
Which of the following is the incorrect statement?
1 \({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can give aldol condensation.
2 When mixture of ethanal and propanal is treated with aq. NaOH , structurally four different aldols are formed.
3 Mixture of HCHO and PhCHO cannot give aldol condensation product.
4 Aldol reaction is possible even if one of the carbonyl compounds contains an \({\mathrm{\alpha-}}\) hydrogen.
Explanation:
\({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can't give aldol condensation as it dosen't have \({\mathrm{\alpha}}\)-Hydrogen. Under the same conditions it gives \({\mathrm{\mathrm{CHCl}_{3}}}\) and \({\mathrm{\mathrm{HCOO}^{-}}}\).
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323463
On treatment of propanone with dilute \(\mathrm{Ba}(\mathrm{OH})_{2}\), the product formed is
1 aldol
2 phorone
3 propionaldehyde
4 4-hydroxy-4-methyl-2-pentanone.
Explanation:
In the presence of \(\mathrm{Ba}(\mathrm{OH})_{2^{\prime}}\) propanone (acetone) undergoes aldol condensation as :
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323464
Assertion : 2 - Butenal lacks enolisable \(\mathrm{H}\) atom, \(\alpha\) to carbonyl group, still it has sufficient acidic character. Reason : The conjugate base of 2 - butenal is stabilised by resonance.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
2 - Butenal contains \(\gamma-\mathrm{H}-\) atoms and the conjugate base obtained after the removal of \(\gamma-\mathrm{H}-\) atom, is stabilised by resonance. Hence, 2 - Butenal is sufficiently acidic. However, it lacks enolisable \(\mathrm{H}\)-atom, \(\alpha\) to carbonyl group.
AIIMS - 2009
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323465
Assertion : Acetaldehyde undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Reason : Aldehydes which do not contain \(\alpha\) hydrogen undergo aldol condensation.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Acetaldehyde which has \(\alpha\)-hydrogen undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Aldehydes lacking \(\alpha\) - hydrogens undergo Cannizzaro reaction, involving self oxidation and reduction upon heating with concentrated alkali. So the option (3) is correct.
323461
Which statement about the aldol condensation is correct?
1 A Lewis acid is commonly used as a catalyst
2 The initial step is probably the formation of a carbanion.
3 A Lewis base is employed to induce carbocation formation
4 The carbon chain is lengthened throuh the elimination of 1 mole of \(\mathrm{H}_{2} \mathrm{O}\)
Explanation:
Conceptual Questions
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323462
Which of the following is the incorrect statement?
1 \({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can give aldol condensation.
2 When mixture of ethanal and propanal is treated with aq. NaOH , structurally four different aldols are formed.
3 Mixture of HCHO and PhCHO cannot give aldol condensation product.
4 Aldol reaction is possible even if one of the carbonyl compounds contains an \({\mathrm{\alpha-}}\) hydrogen.
Explanation:
\({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can't give aldol condensation as it dosen't have \({\mathrm{\alpha}}\)-Hydrogen. Under the same conditions it gives \({\mathrm{\mathrm{CHCl}_{3}}}\) and \({\mathrm{\mathrm{HCOO}^{-}}}\).
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323463
On treatment of propanone with dilute \(\mathrm{Ba}(\mathrm{OH})_{2}\), the product formed is
1 aldol
2 phorone
3 propionaldehyde
4 4-hydroxy-4-methyl-2-pentanone.
Explanation:
In the presence of \(\mathrm{Ba}(\mathrm{OH})_{2^{\prime}}\) propanone (acetone) undergoes aldol condensation as :
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323464
Assertion : 2 - Butenal lacks enolisable \(\mathrm{H}\) atom, \(\alpha\) to carbonyl group, still it has sufficient acidic character. Reason : The conjugate base of 2 - butenal is stabilised by resonance.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
2 - Butenal contains \(\gamma-\mathrm{H}-\) atoms and the conjugate base obtained after the removal of \(\gamma-\mathrm{H}-\) atom, is stabilised by resonance. Hence, 2 - Butenal is sufficiently acidic. However, it lacks enolisable \(\mathrm{H}\)-atom, \(\alpha\) to carbonyl group.
AIIMS - 2009
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323465
Assertion : Acetaldehyde undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Reason : Aldehydes which do not contain \(\alpha\) hydrogen undergo aldol condensation.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Acetaldehyde which has \(\alpha\)-hydrogen undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Aldehydes lacking \(\alpha\) - hydrogens undergo Cannizzaro reaction, involving self oxidation and reduction upon heating with concentrated alkali. So the option (3) is correct.
323461
Which statement about the aldol condensation is correct?
1 A Lewis acid is commonly used as a catalyst
2 The initial step is probably the formation of a carbanion.
3 A Lewis base is employed to induce carbocation formation
4 The carbon chain is lengthened throuh the elimination of 1 mole of \(\mathrm{H}_{2} \mathrm{O}\)
Explanation:
Conceptual Questions
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323462
Which of the following is the incorrect statement?
1 \({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can give aldol condensation.
2 When mixture of ethanal and propanal is treated with aq. NaOH , structurally four different aldols are formed.
3 Mixture of HCHO and PhCHO cannot give aldol condensation product.
4 Aldol reaction is possible even if one of the carbonyl compounds contains an \({\mathrm{\alpha-}}\) hydrogen.
Explanation:
\({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can't give aldol condensation as it dosen't have \({\mathrm{\alpha}}\)-Hydrogen. Under the same conditions it gives \({\mathrm{\mathrm{CHCl}_{3}}}\) and \({\mathrm{\mathrm{HCOO}^{-}}}\).
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323463
On treatment of propanone with dilute \(\mathrm{Ba}(\mathrm{OH})_{2}\), the product formed is
1 aldol
2 phorone
3 propionaldehyde
4 4-hydroxy-4-methyl-2-pentanone.
Explanation:
In the presence of \(\mathrm{Ba}(\mathrm{OH})_{2^{\prime}}\) propanone (acetone) undergoes aldol condensation as :
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323464
Assertion : 2 - Butenal lacks enolisable \(\mathrm{H}\) atom, \(\alpha\) to carbonyl group, still it has sufficient acidic character. Reason : The conjugate base of 2 - butenal is stabilised by resonance.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
2 - Butenal contains \(\gamma-\mathrm{H}-\) atoms and the conjugate base obtained after the removal of \(\gamma-\mathrm{H}-\) atom, is stabilised by resonance. Hence, 2 - Butenal is sufficiently acidic. However, it lacks enolisable \(\mathrm{H}\)-atom, \(\alpha\) to carbonyl group.
AIIMS - 2009
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323465
Assertion : Acetaldehyde undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Reason : Aldehydes which do not contain \(\alpha\) hydrogen undergo aldol condensation.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Acetaldehyde which has \(\alpha\)-hydrogen undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Aldehydes lacking \(\alpha\) - hydrogens undergo Cannizzaro reaction, involving self oxidation and reduction upon heating with concentrated alkali. So the option (3) is correct.
323461
Which statement about the aldol condensation is correct?
1 A Lewis acid is commonly used as a catalyst
2 The initial step is probably the formation of a carbanion.
3 A Lewis base is employed to induce carbocation formation
4 The carbon chain is lengthened throuh the elimination of 1 mole of \(\mathrm{H}_{2} \mathrm{O}\)
Explanation:
Conceptual Questions
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323462
Which of the following is the incorrect statement?
1 \({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can give aldol condensation.
2 When mixture of ethanal and propanal is treated with aq. NaOH , structurally four different aldols are formed.
3 Mixture of HCHO and PhCHO cannot give aldol condensation product.
4 Aldol reaction is possible even if one of the carbonyl compounds contains an \({\mathrm{\alpha-}}\) hydrogen.
Explanation:
\({\mathrm{\mathrm{CCl}_{3} \mathrm{CHO}}}\) can't give aldol condensation as it dosen't have \({\mathrm{\alpha}}\)-Hydrogen. Under the same conditions it gives \({\mathrm{\mathrm{CHCl}_{3}}}\) and \({\mathrm{\mathrm{HCOO}^{-}}}\).
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323463
On treatment of propanone with dilute \(\mathrm{Ba}(\mathrm{OH})_{2}\), the product formed is
1 aldol
2 phorone
3 propionaldehyde
4 4-hydroxy-4-methyl-2-pentanone.
Explanation:
In the presence of \(\mathrm{Ba}(\mathrm{OH})_{2^{\prime}}\) propanone (acetone) undergoes aldol condensation as :
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323464
Assertion : 2 - Butenal lacks enolisable \(\mathrm{H}\) atom, \(\alpha\) to carbonyl group, still it has sufficient acidic character. Reason : The conjugate base of 2 - butenal is stabilised by resonance.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
2 - Butenal contains \(\gamma-\mathrm{H}-\) atoms and the conjugate base obtained after the removal of \(\gamma-\mathrm{H}-\) atom, is stabilised by resonance. Hence, 2 - Butenal is sufficiently acidic. However, it lacks enolisable \(\mathrm{H}\)-atom, \(\alpha\) to carbonyl group.
AIIMS - 2009
CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS
323465
Assertion : Acetaldehyde undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Reason : Aldehydes which do not contain \(\alpha\) hydrogen undergo aldol condensation.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Acetaldehyde which has \(\alpha\)-hydrogen undergoes aldol condensation with dilute \(\mathrm{NaOH}\). Aldehydes lacking \(\alpha\) - hydrogens undergo Cannizzaro reaction, involving self oxidation and reduction upon heating with concentrated alkali. So the option (3) is correct.
