Word Count : 1204

---

Ultraviolet (UV) spectroscopy is an important spectroscopic technique used for the identification and differentiation of organic compounds containing chromophores, conjugated systems, aromatic rings and other groups capable of absorbing ultraviolet radiation. The absorption of UV radiation causes electronic transitions from lower-energy molecular orbitals to higher-energy molecular orbitals. Since different compounds possess different electronic structures, the position and intensity of their absorption bands are characteristic and can be used to distinguish between them. The most important electronic transitions observed in organic compounds are σ → σ*, n → σ*, π → π* and n → π*. The σ → σ* transition requires very high energy and generally occurs below 200 nm, so it is of limited value for routine identification. The n → σ* transition is observed in compounds containing heteroatoms such as oxygen, nitrogen and sulfur. The π → π* transition is particularly useful for compounds containing double bonds, aromatic systems and conjugated unsaturation. The n → π* transition is commonly observed in carbonyl compounds and other molecules containing heteroatoms with lone-pair electrons. The differentiation of organic compounds on the basis of UV spectra mainly depends on λmax, absorption intensity, number of absorption bands and the effect of conjugation and substituents on the absorption maximum. λmax is the wavelength at which maximum absorption occurs. A compound with greater conjugation generally absorbs at a longer wavelength because conjugation decreases the energy difference between the ground and excited electronic states. This movement of the absorption maximum towards a longer wavelength is known as a bathochromic shift or red shift. A movement towards shorter wavelength is called a hypsochromic shift or blue shift. For example, ethene and 1,3-butadiene can be differentiated by their UV spectra. Ethene contains one isolated double bond and therefore shows a π → π* transition at a relatively short wavelength, ___ ________ ____ ______ ___ ________.
_________ ______ _________ _______ ____ _____ _______ _______ _________ ____ _______.
______ ___ _____ __________ ______ ______.
__________ ________ ________ _______ ___ ___.
___ _____ ___ ____ __________ ___ ___ ____ ____ __________ ___ ___.
_____ ____ ________ _____ ______.
_______ ________ _______ ___ _____ ______ _____.
_____ ___ _______ ______ __________ ________ ___ __________.
__________ ________ _____ _________ __________.
______ _________ _________ __________ _________ ________.
______ _____ _______ _______ ________ _____ _________ _____.
______ _____ _____ _______ ________ _________ ____ ______ ___ ____ ________ ____.
______ _____ ______ _____ ___ ______ ________ ____ ______ __________ _______.
__________ ___ ______ _____ ________ ________ ____ _______ ____ ______ _____ _____.
____ ______ ______ _________ ____ __________ ________ _______ __________.
__________ _________ ____ ___ _____ ____ _________ ___ _____ __________ _____.
___ ______ _________ _______ _________ ___ ____ __________ ________.
__________ ________ ________ _______ _______ _________ _____ _________.
______ _____ ________ ________ _________ ______ __________ ____ _______.
________ _______ ____ __________ ____ _______ _____ ___ ________ ________.
________ ____ ___ ______ ____ _________.
_________ ____ ________ _________ _________ _______.
____ _______ _______ _________ ___ __________ ________.
_______ _____ ________ ___ ____ ________ ______ ____ _____ ________ _______.
____ ____ _______ _________ _____.
____ _________ _______ _________ _______.
______ _________ _____ __________ ______ _______ _____ ____ __________ _________ _________.
___ _______ _______ ____ ________ _______ __________ ________ _______ ___.
___ _______ ______ ____ ________ _________ __________.
________ ________ _____ _______ __________ ________ ________ _____ ______.
____ ____ _____ ____ ___ _____ __________ ________ ________ _______ ________.
_______ _____ ________ ___ _____ _________ ___ __________ ______ __________ _________ _______.
_______ _____ __________ ______ __________ ____ ________.
____ ___ ____ ______ ________ ______ _________ _________ ________.
_______ ____ _______ _______ ______ ______ ___ _______ ____ _______ ____.
____ __________ _____ ________ _____.
________ ___ ________ _________ ____ ______ _________ _____ ____ ________ _____ ___.
______ ________ __________ ______ _____ __________ _________ ______.
_______ ___ ___ ___ ____ __________ ______ ______ _____ ________ ____ _______.
_____ ________ ______ _____ ______ ____.
__________ _________ ______ __________ ______ ____ __________ ____ ________ ___ __________ ______.
_____ ___ _______ ________ _______ _______ _________ ______ _______.
_______ _____ ________ _____ ____ _______.
______ ____ _______ ___ __________.
_____ _________ ________ ______ ______.
______ ___ _________ ____ _______ ________ ______ _____.
__________ ________ ___ __________ _________ ___ ___ ______.
________ ______ _____ ____ _______ _____ _______ ______ ___.
________ ________ _________ _______ _________ ____ _______ ____.
_________ _________ __________ _________ _______ _____ _____ _________.
_________ ________ ___ ____ _______ __________.
______ ________ _______ ______ __________ ______ ________ __________.
__________ __________ ___ __________ _________ _________ ____.
___ _____ _____ _______ _______.
___ ___ ______ ______ ________.
____ _______ _______ ________ ____ ____ _________ ____.
_____ ____ ______ ______ ________ ______ _______.
________ ______ ____ _________ _______ _________ _______ ________ ______ _____ _______.
________ _______ _____ ______ ___ _______ _________ ______ ______.
________ _______ ________ __________ _____ ___ ______ ______ ______.
____ _____ ___ ___ _________ ____.
____ _____ __________ __________ ________ _____ ________ ____ _____ _______.
_____ ________ ________ ____ _______ _______ _______ ______.
__________ ________ _______ ______ ____ _______ ___ __________ _______ ________ ______.
________ ___ ____ ______ _______ _______ ________ ______ ________ _____ ______ ______.
___ ___ ______ ______ ______ ________ _____ ___ __________ ________.
_______ __________ __________ __________ ______.
_________ ________ _________ __________ __________ __________ _________ ________ _________.
_________ _________ ____ ___ ____ ______.
______ _______ _________ _____ ______ _____ ______.
_________ _____ _________ ______ _____ _____ ________ _______ ____ ____ ________ _______.
___ ____ ______ ____ ___ _________ _______ __________ _________ _____ _________.
________ _____ ____ ___ ________ ____.
_____ __________ _____ ______ __________ _________.
_________ _______ ____ __________ _______ ___ _____.
_______ _______ _________ ____ _________.
______ _____ ______ ___ _____ _____.
________ ____ _______ ___ _____ ________ ___ _________ _____ __________ _____.
______ _____ ______ _________ _________ ________ ______ _________ ____ ____.
________ ________ _________ ___ ______ _________ _____ ______.
_________ ___ _________ ________ __________ _________.
___ _________ ____ ____ ____ ___ ____ ________ ________.
_______ _________ _________ ________ ______ ____.
______ ______ _____ ______ _________ _________ __________ _______ ______.
_________ __________ ______ __________ _________ ______ _____ ______ ______ _____ ______ ______.
_____ ____ ___ ____ ______ __________ _________ ___ _________ _____.
________ ___ ________ ________ __________ _____ _______ ____ ______ _______.
____ ____ _______ ____ _______.
_______ __________ _______ ___ ________ _________ ____ ____ ___ ______ _______ _______.
___ ___ ____ ________ ________ ______ _____ __________ _______ ____ ___.
______ _____ ___ ____ ________ ______ _________ __________ _____ ______.
__________ ________ _______ ___ _________ ___ __________ _________ _____ _______ __________ _______.
________ _________ __________ ____ ______ __________ _______ ___ __________ _________.
_____ _______ ____ ________ ____ _________ _________ _________ ______.
__________ ___ __________ _______ _____ ___ _________ ___ ______ _____ _______ ________.
________ __________ ___ ________ _______.
___ _____ _________ ____ ______ _____ ________ _______ __________ ____ ______.
____ ______ ___ _____ ______ ___ _____ ____.
_____ ______ _______ _________ __________ _____ ________ _______ _________ _______.
_____ ___ _______ __________ ____ __________ ___ ______ _______.
_____ _____ ___ _____ ______ _____ _________ ________.
________ __________ _______ ___ __________ ___.
_________ _______ __________ _____ _________ _______ ________ _________ _____ ____ _______.
_______ ___ ________ ___ _________ _________ ______ ________ ___ ________ _____.
_________ _______ __________ _______ _____ ___ _________ _________ __________ _________.
________ ______ ________ ______ __________ ____ _________ _______ ______ _________ _____.
Get Full Answer on WhatsApp