unit-iv -poc-1

Which factor makes aldehydes more reactive than ketones towards nucleophilic addition?

• Steric hindrance is less in aldehydes

• +I effect is stronger in aldehydes

• Aldehydes are aromatic

• Ketones have less electrophilic carbonyl carbon

Which of the following is NOT a nucleophile that adds to carbonyl compounds?

• HCN

• NH₃

• RMgX

• O₂

The electromeric effect is:

• Permanent displacement of σ-electrons

• Temporary complete transfer of π-electrons in presence of reagent

• Delocalization of electrons throughout the molecule

• Permanent withdrawal of electrons due to electronegative atom

In the presence of HCN, the electromeric effect in carbonyl group shifts electron pair towards:

• Oxygen atom

• Carbon atom

• Hydrogen atom

• Cyanide ion

Aldol condensation requires:

• Acid or base catalyst

• Strong oxidizing agent

• Zn/Hg catalyst

• UV light

The product of aldol condensation is:

• Alcohol only

• Aldehyde

• β-hydroxy aldehyde/ketone

• Ester

Crossed aldol condensation involves:

• Same aldehyde

• Aldehyde + ketone

• Carboxylic acids

• Amines

Acetaldehyde on aldol condensation followed by dehydration gives:

• Ethanol

• Crotonaldehyde

• Acetic acid

• Formalin

Cannizzaro reaction occurs with aldehydes:

• Having α-hydrogen

• Lacking α-hydrogen

• Both a and b

• Only ketones

Which aldehyde undergoes Cannizzaro reaction?

• Acetaldehyde

• Formaldehyde

• Acetone

• Benzophenone