Answer to Question #86552 in Organic Chemistry for Chanchal

Question

Among the molecule given below , identify those which are microwave active .justify your answer .
I2, HBr , co2, cs2, NO

Answer 1

The molecule gives a arotational spectrum (is micriwave active) only if it has a permanent dipole moment.

1. I₂ is a homonuclear diatomic molecule. The molecule is linear. There is no diffference in electronegativities between the atoms of iodine, hence the molecule is non polar and mictowave inactive.

2.HBr is heteronuclear diatomic molecule. The molecule is linear. The molecule is polar as bond is formed between two atoms of different electronegativity. Hence the molecule is microwave active.

3.CO₂ is a linear molecule. Each bond C=O has a dipole moment as this bond is formed by two atoms different in electronegativity. But the net dipole moment of a molecule is zero as two dipole moments cancel out. Hence CO₂ is microwave inactive.

4.CS₂ is a linear molecule. Each bond C=S has a dipole moment as this bond is formed by two atoms different in electronegativity. But the net dipole moment of a molecule is zero as two dipole moments cancel out. Hence CS₂ is microwave inactive.

5.NO is heteronuclear diatomic molecule. The molecule is linear. The molecule is polar as bond is formed between two atoms of different electronegativity. Hence the molecule is microwave active.