91Ó°ÊÓ

The absorption spectrum has dark lines in the spectrum when radiation is transmitted through a substance, indicating absorption at specific wavelengths of electromagnetic radiation.

The given chart has values for absorption of particular wavelength radiation by specific functional group.

Here three functional groups are present namely aromatic ring, nitro group and aldehyde group. Red atom indicated here is oxygen and the blue atom is nitrogen according to bookconvention.

Here four absorption bands will be seen:

• Nitro group absorption band is seen at 1540 cm^-1.
• Aldehyde group absorption band is at 1730cm^-1 .
• Aromatic ring -C = C - band at 1450-1600 cm^-1 .
• Aromatic ring C- H band at3030 cm^-1 .

Here two functional groups are present namely ester and alkene group. Red atom indicated here is oxygen.

Here three absorption bands will be seen:

• Ester group absorption band is seen at 1735 cm^-1 .
• Alkene -C = C - band at1640-1680cm^-1 .
• Alkene = C- H band at3020-3100 cm^-1 .

Here two functional groups are present namely the ketone and alcoholgroups. The red atom indicated here is oxygen.

Here four absorption bands will be seen:

• Ketone group absorption band is seen at 1715 cm^-1 .
• Alcohol group absorption band is at 3400-3650cm^-1 .