NEETChemistryAldehydes and Ketones
Give a plausible explanation for the following statement: There are two –NH 2 groups in semicarbazide. However, only one is involved in the formation of semicarbazones.
Options
- AThe -NH 2 group that is not involved in the formation of semicarbazones is sterically hindered and cannot easi
- BSemicarbazide has two amino (NH 2 ) groups, out of which one is involved in resonance as shown above. Electron
- CThe -NH 2 group that is not involved in semicarbazone formation is in a different chemical environment and doe
- DSemicarbazide can undergo tautomerization in solution, leading to the selective participation of one -NH 2 gro
Correct answer
B. Semicarbazide has two amino (NH 2 ) groups, out of which one is involved in resonance as shown above. Electron
Step-by-step solution
Correct Option is : (B) Semicarbazide has two amino (NH 2 ) groups, out of which one is involved in resonance as shown above. Electron-density on this (NH 2 ) decreases and it does not act as a nucleophile. But the other (NH 2 ) group (attached to NH) has a lone pair of electrons which are not involved in resonance. So, this pair is available for the nucleophilic attack on the carbonyl group (>C=O) of aldehydes and/or ketones.