Question

70. In IR spectroscopy, the vibration between atoms is caused by which of the following
A. The overall molecular weight of the molecule
B. Dipole moments between atoms
C. The number of protons in a nucleus
D. The movement of electrons to higher energy levels
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Answer 1

Answer:

B

Explanation:

Dipole between atoms

Answer 2

Vibration between atoms in IR spectroscopy is caused by B) Dipole moments between atoms.

Explanation:

• IR spectroscopy is a technique used to identify chemical compounds based on how infrared radiations are absorbed by the compounds chemical bonds and interact with them.

• IR spectroscopy detects the absorption of light by a compound in IR region of electromagnetic spectrum.

• To absorb light a molecule must have a bond within its structure that can exhibit what is referred to as a "dipole moment" which means electrons within a bond are shared equally.

• For absorbing IR, the vibration or rotations within the molecule must cause a net change in the dipole moment of the molecule.

• A permanent dipole is not necessary as the rule requires only a change in dipole moment.