Chemistry Aldehydes & Ketones MDCAT 2016
PMDC Verified Question 76 of 94
\( R-CH=N-NH-C_6H_3(NO_2)_2 \). It is a general formula of:
A
2,4 dinitrophenyl hydrazine
B
Phenyl hydrazone
C
1,3 dinitrophenyl hydrazone
D
2,4 dinitrophenyl hydrazone
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: 2,4 dinitrophenyl hydrazone
Concept:

The nomenclature of the product reflects both the carbonyl parent and the hydrazine derivative used in the condensation reaction.

Solution:

  • The reactant used is 2,4-dinitrophenylhydrazine (often abbreviated as 2,4-DNPH).


  • When this hydrazine derivative reacts with a carbonyl compound, water is eliminated and a \( C=N \) double bond is formed.


  • The suffix of the functional group changes from '-hydrazine' to '-hydrazone'.


  • Therefore, the generic product \( R-CH=N-NH-C_6H_3(NO_2)_2 \) is called a 2,4-dinitrophenylhydrazone.


Why other options are incorrect:

Option A is the reactant, not the product. Option B lacks the nitro groups on the benzene ring. Option C has incorrect numbering (the nitro groups are at the 2 and 4 positions relative to the hydrazine linkage, not 1 and 3).

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