Teaching Haryana (HPSC) Assistant Professor Mock Test 2025 Chemical Sciences Characterisation of Inorganic Compounds UV-Vis Spectroscopy
The peaks in the 320-380 nm portion of the UV absorption spectrum of pyridine shift toward the blue portion of the spectrum when the solvent changes from hexane to methanol. This phenomenon can be attributed to:
1
The increase in the energy of the π-orbital due to the change in solvent.
2
The decrease in the energy of the n and π* orbitals, with the n orbital experiencing a greater decrease, leading to a hypsochromic shift.
3
The interaction between π-orbitals of pyridine and the non-polar nature of methanol.
4
The formation of hydrogen bonds between hexane and the nitrogen atom in pyridine.
5
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