Question

Predict the wavelength of absorption band in the UV spectrum of the below shown structure:

• A. 252 mn
• B. 248 nm
• C. 244 nm
• D. 240 nm

Answer 1

The Correct Option is D

The question asks for the predicted wavelength of the absorption band in the UV spectrum for the given structure. The structure shown is naphthalene, a polycyclic aromatic hydrocarbon. 

In UV-Visible spectroscopy, the absorption band corresponds to electronic transitions. In aromatic hydrocarbons like naphthalene, these transitions typically arise from π to π* transitions. The wavelength at which these transitions occur depends on several factors, including the molecular structure and conjugation.

Naphthalene is known to have strong absorbance mainly due to its aromatic system. Standard data from literature suggests that the main absorption maximum for naphthalene occurs at around 220-245 nm in the UV spectrum.

Given the options:

• 252 nm
• 248 nm
• 244 nm
• 240 nm

 

The typical UV absorption band for naphthalene appears around 220 nm to 240 nm. Considering this, the option that best matches the expected value from literature for a naphthalene molecule is 240 nm.

Conclusion: The predicted wavelength of the absorption band in the UV spectrum for the given structure (naphthalene) is 240 nm.