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Which of the following could happen when infrared radiation is absorbed by a molecule ?

A) molecules begins to rotate more rapidly
B) molecule may glow in the dark
C) Electrons are promoted from filled to empty molecular orbitals
D) The orientation of a nuclear spin state changes.
E) intramolecular bond angles change

1 Answer

3 votes

Answer:

E) Intramolecular bond angles change

Step-by-step explanation:

Infrared Radiation:

IR is electromagnetic radiations. The wavelength i.e. 700nm to 1000 mm of infrared is longer than invisible light and Its frequency is lower than light, that's why it is invisible to light.

  • When IR radiation strike the molecule it absorbed by this molecule.
  • This radiation used to identify and study chemicals.
  • Infrared radiation interact with intra-bonds of the molecule.
  • Bonds in the molecules have vibrational translational and rotational movements
  • Due to these vibration, rotation and translation movement it absorb a radiation of specific frequency and wavelength
  • These movements of bond are very small and absorbs radiations of very low frequency
  • So when Infrared light or radiation absorbed the intra-bonds of the molecule get affected and angles of these bonds changes.
  • As the frequency of the absorbed radiation matches the frequency of the bond that vibrates.

So

The correct option is option E

E) Intramolecular bond angles change

* Note:

it couldn't be option A as the frequency of IR is not enough to rotate a whole molecule

It Couldn't be option B as IR rations are electromagnetic radiation of longer wave length so it one can not see it with light so how it will glow a molecule

It also not could be the option C as for the excitation of electrons require much higher energy.

It also not the option D as nuclear magnetic spin is associated with nuclear magnetic radiation that are much different from IR.