Chemistry Aldehydes & Ketones ETEA 2016
PMDC Verified Question 78 of 94
The compound Aldehyde hydrazine is:
A
\( R-CH=N-NH_2 \)
B
\( R_2C=N-NH_2 \)
C
\( R-CH=N-O-NH_2 \)
D
\( R-CH=O-N=NH \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: \( R-CH=N-NH_2 \)
Concept:

When hydrazine (\( H_2N-NH_2 \)) reacts with a carbonyl compound, water is eliminated to form a hydrazone.

Solution:

  • An aldehyde has the general structure \( R-CHO \).


  • Reacting it with hydrazine removes the oxygen from the aldehyde and two hydrogens from one of the nitrogens in hydrazine.


  • This forms a double bond between the aldehyde carbon and the nitrogen, resulting in the structure \( R-CH=N-NH_2 \).


  • While commonly called a hydrazone, the option representing the "aldehyde hydrazine" (hydrazone) is clearly A.


Why other options are incorrect:

Option B represents a ketone hydrazone (two R groups on the carbon). Options C and D are chemically nonsensical structures with incorrect valencies and bonding for this reaction.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Previous Question All Aldehydes & Ketones MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App