MolSynapsequestion bank
MolSynapse / Question bank / Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition / Nucleophilic addition to aldehydes and ketones
JEE Main levelSingle correct optionDifficulty 2 of 3o1074

Chloral, , forms an isolable crystalline hydrate, but acetaldehyde does not. The main reason is that

  1. Athe strongly electron-withdrawing group lowers the stability of the carbonyl form relative to the gem-diol, so the hydrate is favoured at equilibrium
  2. Bthe group is bulky and prevents water from approaching the carbonyl carbon
  3. Cchloral is a stronger base than acetaldehyde and is protonated by water
  4. Dchloral has an alpha hydrogen that is easily enolised

Answer: A

The three chlorine atoms withdraw electrons by the -I effect, increasing the partial positive charge on the carbonyl carbon and destabilising the carbonyl form relative to the tetrahedral hydrate. The equilibrium therefore lies on the side of the gem-diol, .
Practice Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition More on Nucleophilic addition to aldehydes and ketones
Previous questionNext question

More questions on Nucleophilic addition to aldehydes and ketones