UPSC Combined Geo-Scientist, Mains · 2018 · Mains Paper III
Q10(c)(v). Longest-wavelength diene band
Question
Among the depicted fused-ring dienes, choose the highest λₘₐₓ: I isolated double bonds, II conjugated in one ring, III conjugated across two rings.
Answer in brief
II, the homoannular conjugated diene.
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CoversLongest-wavelength diene bandUV conjugation
All parts of Question 10
- 10(a) Phenolic OH band shapes5 marks
- 10(b) Cyclic ether identification5 marks
- 10(c)(i) Most downfield proton2 marks
- 10(c)(ii) Highest carbonyl frequency2 marks
- 10(c)(iii) Odd nominal molecular mass2 marks
- 10(c)(iv) Most upfield carbon2 marks
- 10(c)(v) Longest-wavelength diene band2 marks
- 10(d) Phenethyl alcohol spectra10 marks