Question

Among the molecules given below identify those which are microwave active justify your answer I2,HBr,CO2,CS2,NO

Answer 1

Out of all the molecules given, only NO ( nitric oxide) and HBr ( Hydrogen bromide) are microwave active.

The important factor for a molecule to be microwave active is dipole moment. A molecule should possess a permanent dipole moment for it to get a rotational spectrum.

Homonuclear molecules are not microwave active so I2 is inactive, CO2 and CS2 have net zero dipole moment so only HBr and NO qualify as microwave active molecules.