#carbonyl compounds

Reactions due to α-Hydrogen - Aldol, Cannizzaro and Acidity of Carboxylic Acids

Arrange in increasing order of reactivity with NH₂OH: CH₃CH₂CHO, CH₃COCH₂CH₃, C₆H₅CHO.

Reactivity decreases with steric hindrance and conjugation: CH₃COCH₂CH₃ (ketone) < C₆H₅CHO (aromatic aldehyde) < CH₃CH₂CHO (aliphatic aldehyde).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Reactions due to α-Hydrogen - Aldol, Cannizzaro and Acidity of Carboxylic Acids

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which aldehyde reacts with itself under basic conditions to form a β-hydroxy aldehyde with six carbons?

Butanal (CH₃CH₂CH₂CHO) undergoes self-aldol condensation to form 2-ethyl-3-hydroxyhexanal (CH₃CH₂CH₂CH(OH)CH(CH₂CH₃)CHO), a six-carbon β-hydroxy aldehyde.

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which reaction converts CH₃CH₂CHO to CH₃CH\=CHCHO?

Propanal (CH₃CH₂CHO) undergoes aldol condensation with itself, forming an aldol product that dehydrates to but-2-enal (CH₃CH\=CHCHO).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which compound gives a silver mirror with Tollens' reagent but not a yellow precipitate with iodoform reagent?

Propanal (CH₃CH₂CHO) is an aldehyde (positive Tollens' test) but lacks a CH₃C\=O group (negative iodoform test).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which compound does not give a positive Tollens' test?

Tollens' test is specific to aldehydes. Cyclohexanone (C₆H₁₀O), a ketone, does not reduce Tollens' reagent.

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which reagent distinguishes between ethanal and benzaldehyde?

Fehling’s solution oxidizes aliphatic aldehydes like ethanal (CH₃CHO) to form a red precipitate, but does not react with aromatic aldehydes like benzaldehyde (C₆H₅CHO).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which compound gives a positive Fehling’s test and undergoes aldol condensation?

Propanal (CH₃CH₂CHO) is an aliphatic aldehyde (positive Fehling’s test) with α-hydrogens (undergoes aldol condensation).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which compound produces a red precipitate with Fehling’s solution and has six carbon atoms?

Hexanal (CH₃CH₂CH₂CH₂CH₂CHO), a six-carbon aliphatic aldehyde, reduces Fehling’s solution to form a red Cu₂O precipitate.

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Arrange in increasing order of reactivity towards HCN: Acetone, Acetaldehyde, Di-tert-butyl ketone.

Reactivity decreases with steric hindrance. Di-tert-butyl ketone (bulky) < Acetone (less hindered) < Acetaldehyde (least hindered, aldehyde more reactive).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Arrange in decreasing order of reactivity towards HCN: (CH₃)₂CHCHO, CH₃CH₂COCH₃, CH₃CHO.

Reactivity: CH₃CHO (simple aldehyde) > (CH₃)₂CHCHO (branched aldehyde) > CH₃CH₂COCH₃ (ketone, steric hindrance).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Arrange in increasing order of reactivity with HCN: CH₃CHO, CH₃COCH₃, C₆H₅CHO.

Reactivity with HCN decreases with steric hindrance and increases with electrophilicity: CH₃COCH₃ (ketone) < C₆H₅CHO (aromatic aldehyde) < CH₃CHO (aliphatic aldehyde).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details

Nomenclature, Structure and Preparation of Aldehydes and Ketones

Which compound is formed when butanal reacts with HCN?

Butanal (CH₃CH₂CH₂CHO) reacts with HCN to form butanal cyanohydrin (CH₃CH₂CH₂CH(OH)CN).

Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Nomenclature, Structure and Preparation of Aldehydes and Ketones

View Details