Explain the principle of infrared spectroscopy.

Explanation:

IR (infrared) spectroscopy theory is based on the concept that the molecules tend to absorb some specific amount of the frequencies of light which are characteristic of corresponding structure of molecules. These energies are reliant on shape of molecular surfaces, associated vibration coupling, and mass corresponding to atoms.

It is used to detect the type of the functional group present in the organic compound.

he would use the colour black

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.