00:01
Hello students, in this question we have to discuss the vibrations in co2 molecule which are ir active.
00:07
So, we have the first vibration that is symmetric stretching.
00:15
So, if the both oxygen atom are oscillating in the same direction in such a way that they are in same phase.
00:28
So, at any time the distance between oxygen atom and carbon atom will be same for both the oxygen atoms.
00:38
Hence, the dipole moment will always be zero for symmetric type of stretching.
00:48
So, this mode of vibration will be ir inactive.
00:56
However, if the vibrations of both the carbon double bond oxygen bonds are not in same phase then that type of stretching will be known as the asymmetric stretching.
01:16
So, the carbon oxygen bond lengths now will not be equal at every time.
01:24
For example, at one point one bond will be longer and other bond will be shorter.
01:31
So, a dipole moment will be created due to the difference in electronegativities...