Indian Forest Service (Mains), Chemistry optional · 2023 · Paper II
Q6(c). Two C3H6O carbonyl compounds
Question
Two C₃H₆O compounds give 2,4-DNPH precipitates. How can IR identify their functional groups?
Answer in brief
The usual pair is propanal and propanone. Both show C=O, but propanal also shows the diagnostic aldehydic C–H absorption pair.
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CoversIR spectroscopypropanal vs propanone2,4-DNP testaldehydic C–H stretchFermi doublet
All parts of Question 6
- 6(a) Selective reduction and alpha oxidation10 marks
- 6(b) Photochemical alpha cleavage10 marks
- 6(c) Two C3H6O carbonyl compounds5 marks
- 6(d) Meaning of a coupling constant5 marks
- 6(e) Intensity of alkene and ketone UV absorption5 marks
- 6(f) Isotopic substitution in rotational spectra5 marks