Q: An organic compound with the molecular formula \$C_9H_{10}O\$ forms 2,4-DNP derivative, reduces Tollens reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzenedicarboxylic acid. Identify the compound.

An organic compound with the molecular formula \$C_9H_{10}O\$ forms \$2,4\$-DNP derivative and also reduces Tollens reagent.Hence, the compound is an aldehyde.The compound undergoes Cannizzaro reaction. Hence, it does not contains an alpha H atom.On vigorous oxidation, it gives \$1,2\$-benzenedicarboxylic acid. Hence, -CHO group is directly attached to benzene ring and the compound is ortho di-substituted benzene.The compound.is \$2\$-ethylbenzaldehyde.

Q: How will you convert ethanal into the following compounds?(i) Butane-1,3-diol (ii) But-2-enal (iii) But-2-enoic acid

(i) Ethanal into Butane-\$1,3\$-diol Aldol condensation (in presence of dil NaOH) followed by reduction with sodium borohydride.(ii) Ethanal into But-\$2\$-enal Aldol condensation (in presence of dil NaOH) followed by dehydration.(iii) Ethanal into But-\$2\$-enoic acidAldol condensation (in presence of dil NaOH) followed by dehydration and oxidation with Tollen's reagent.

Q: Explain Aldol condensation with one example.

Aldehydes having \$\alpha hydrogen\$ undergo self condersation on warming with dilute or mild base to give p-hydroxy aldahydes called aldols. This reaction is called aldol condersation.eg.

Question 1

The major product of the following reaction is:

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Question 2

An organic compound with the molecular formula $C_9H_{10}O$ forms 2,4-DNP derivative, reduces Tollens reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzenedicarboxylic acid. Identify the compound.

Accepted Answer

An organic compound with the molecular formula $C_9H_{10}O$ forms $2,4$-DNP derivative and also reduces Tollens reagent.Hence, the compound is an aldehyde.The compound undergoes Cannizzaro reaction. Hence, it does not contains an alpha H atom.On vigorous oxidation, it gives $1,2$-benzenedicarboxylic acid. Hence, -CHO group is directly attached to benzene ring and the compound is ortho di-substituted benzene.The compound.is $2$-ethylbenzaldehyde.

Question 3

How will you bring about the following conversions in not more than two steps?

(i) Propanone to Propene (ii) Benzoic acid to Benzaldehyde
(iii) Ethanol to 3-Hydroxybutanal (iv) Benzene to m-Nitroacetophenone
(v) Benzaldehyde to Benzophenone (vi) Bromobenzene to 1-Phenylethanol
(vii) Benzaldehyde to 3-Phenylpropan-1-ol (viii) Benazaldehyde to $α$ -Hydroxyphenylacetic acid
(ix) Benzoic acid to m- Nitrobenzyl alcohol

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Question 4

Aldehydes are more reactive toward nucleophillic addition reactions than ketones. Justify.

Accepted Answer

Aldehydes are generally more reactive than ketones in nucleophilic addition reactions due to steric and electronic reasons. Sterically, the presence of two relatively large substituents in ketones hinders the approach of nucleophile to carbonyl carbon than in aldehydes having only one such substituent. Electronically, two alkyl groups reduce the electrophilicity of the carbonyl carbon more effectively in ketones than in aldehyde.Hence Aldehydes are more reactive toward nucleophilic addition reactions than Ketones.

Question 5

How will you convert ethanal into the following compounds?(i) Butane-1,3-diol              (ii) But-2-enal                    (iii) But-2-enoic acid

Accepted Answer

(i) Ethanal into  Butane-$1,3$-diol Aldol condensation (in presence of dil NaOH) followed by reduction with sodium borohydride.(ii) Ethanal into But-$2$-enal Aldol condensation (in presence of dil NaOH) followed by dehydration.(iii) Ethanal into But-$2$-enoic acidAldol condensation (in presence of dil NaOH) followed by dehydration and oxidation with Tollen's reagent.

Question 6

Explain Aldol condensation with one example.

Accepted Answer

Aldehydes having $\alpha hydrogen$ undergo self condersation on warming with dilute or mild base to give p-hydroxy aldahydes called aldols. This reaction is called aldol condersation.eg.

Question 7

Acetaldehyde reacts with NaOH to form :-

Accepted Answer

Acetaldehyde reacts with NaOH to form beta hydroxy butyraldehyde. This is an example of aldol condensation reaction and is given by aldehydes or ketones having alpha hydrogen atom.

Question 8

Cannizzaro reaction is not given by:

Accepted Answer

Hint: Cannizaro reaction is shown by aldehydes and ketones that don't have alpha hydrogen (hydrogen on the carbon next to the carbonyl carbon).The compounds that don't have an $\alpha-H$ show Cannizzaro reaction and the compounds that have an $\alpha -H$ show aldol reaction.A)In trimethyl acetaldehyde there are $3$ $CH_3$ group attached to the $\alpha \ C$ and no $\alpha \ H$.So, it will give Cannizzaro reaction.B) Acetaldehyde have $3 \alpha H$ present next to the $C=O$ group so it does not give Cannizzaro reactionC} In benzaldehyde there is a benzyl group on $\alpha \ C$ So, No $\alpha \ H$ So, it will give Cannizzaro reaction.D) In formaldehyde there is no $\alpha  C$ so it will show Cannizzaro reaction.Final answer: Option $B$.

Question 9

In the reaction, $C_6H_5COCH_3\xrightarrow[Zn-Hg/conc.\ HCl]{[H]}X$. X is:

Accepted Answer

The reaction of aldehydes and ketones with zinc amalgam (Zn/Hg alloy) in concentrated hydrochloric acid, which reduces the aldehyde or ketone to a hydrocarbon, is called Clemmensen reduction.

Question 10

Write structures of the products of the following reactions:(i)$CH_3-CH=CH_2 \xrightarrow []{H_2O/H}$(iii)$CH_3-CH_2-\underset { |\ CH_3 }{ CH } -CHO  \xrightarrow []{NaBH_4}$

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Revise with Concepts

Chemical Properties of Aldehydes and Ketones - Nucleophilic Addition Reactions

Chemical Properties of Aldehydes and Ketones - Nucleophilic Addition Reactions followed by Loss of Water

Chemical Properties of Aldehydes and Ketones - Oxidation

Aldol Condensation

Cannizzaro Reaction and Electrophilic substitution reactions in Aldehydes and Ketones

Chemical Properties of Aldehydes and Ketones-Reduction

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Quick Summary With Stories

Nucleophilic Addition Reactions of Aldehyde and Ketone-I

Nucleophilic Addition Reactions of Aldehyde and Ketone-II

Nucleophilic Addition Reactions of Aldehyde and Ketone-III

Nucleophilic Addition reactions of aldehydes and ketones-IV

Nucleophilic Addition reactions of aldehydes and ketones-V

Nucleophilic addition reactions of aldehydes and ketones-VI

Nucleophilic Addition Reactions of aldehydes and ketones-VII

Reduction of Aldehydes and Ketones

Aldol Condensation - Reaction and Mechanism - I

Aldol Condensation - Reaction and Mechanism - II

Intramolecular Aldol Condensation

Crossed Aldol Condensation

Cannizaro Reaction

Crossed Cannizaro Reaction

The major product of the following reaction is:

An organic compound with the molecular formula $C_{9} H_{10} O$ forms 2,4-DNP derivative, reduces Tollens reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzenedicarboxylic acid. Identify the compound.

Aldehydes are more reactive toward nucleophillic addition reactions than ketones. Justify.

How will you convert ethanal into the following compounds?
(i) Butane-1,3-diol (ii) But-2-enal (iii) But-2-enoic acid

Explain Aldol condensation with one example.

Acetaldehyde reacts with NaOH to form :-

Cannizzaro reaction is not given by:

In the reaction, $C_{6} H_{5} C O C H_{3} [H] Z n - H g / c o n c . H C l X$ . X is:

Write structures of the products of the following reactions:
(i) $C H_{3} - C H = C H_{2} H_{2} O / H$
(iii) $C H_{3} - C H_{2} - ∣ C H_{3} C H - C H O N a B H_{4}$

Revise with Concepts

Chemical Properties of Aldehydes and Ketones - Nucleophilic Addition Reactions

Chemical Properties of Aldehydes and Ketones - Nucleophilic Addition Reactions followed by Loss of Water

Chemical Properties of Aldehydes and Ketones - Oxidation

Aldol Condensation

Cannizzaro Reaction and Electrophilic substitution reactions in Aldehydes and Ketones

Chemical Properties of Aldehydes and Ketones-Reduction

Learn with Videos

Quick Summary With Stories

Nucleophilic Addition Reactions of Aldehyde and Ketone-I

Nucleophilic Addition Reactions of Aldehyde and Ketone-II

Nucleophilic Addition Reactions of Aldehyde and Ketone-III

Nucleophilic Addition reactions of aldehydes and ketones-IV

Nucleophilic Addition reactions of aldehydes and ketones-V

Nucleophilic addition reactions of aldehydes and ketones-VI

Nucleophilic Addition Reactions of aldehydes and ketones-VII

Reduction of Aldehydes and Ketones

Aldol Condensation - Reaction and Mechanism - I

Aldol Condensation - Reaction and Mechanism - II

Intramolecular Aldol Condensation

Crossed Aldol Condensation

Cannizaro Reaction

Crossed Cannizaro Reaction

The major product of the following reaction is:

An organic compound with the molecular formula C9​H10​O forms 2,4-DNP derivative, reduces Tollens reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzenedicarboxylic acid. Identify the compound.

Aldehydes are more reactive toward nucleophillic addition reactions than ketones. Justify.

How will you convert ethanal into the following compounds? (i) Butane-1,3-diol (ii) But-2-enal (iii) But-2-enoic acid

Explain Aldol condensation with one example.

Acetaldehyde reacts with NaOH to form :-

Cannizzaro reaction is not given by:

In the reaction, C6​H5​COCH3​[H]Zn−Hg/conc. HCl​X. X is:

Write structures of the products of the following reactions: (i)CH3​−CH=CH2​H2​O/H​ (iii)CH3​−CH2​−∣CH3​CH​−CHONaBH4​​

An organic compound with the molecular formula $C_{9} H_{10} O$ forms 2,4-DNP derivative, reduces Tollens reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzenedicarboxylic acid. Identify the compound.

How will you convert ethanal into the following compounds?
(i) Butane-1,3-diol (ii) But-2-enal (iii) But-2-enoic acid

In the reaction, $C_{6} H_{5} C O C H_{3} [H] Z n - H g / c o n c . H C l X$ . X is:

Write structures of the products of the following reactions:
(i) $C H_{3} - C H = C H_{2} H_{2} O / H$
(iii) $C H_{3} - C H_{2} - ∣ C H_{3} C H - C H O N a B H_{4}$