Question

How might you use IR spectroscopy to determine whether the reaction is really complete after 35-40 min?  

Answer 1

IR spectroscopy is used for identification of organic compounds , as molecules absorbs specific frequencies of light between 4000cm-1 and 400cm-1 based on their bond arrangement and functional groups.The absorbed frequencies are resonant frequencies which is the frequency of the absorbed radiation that matches the transition energy of the bond or group that vibrates. This transition energy ,in turn is determined by various factors like the shape of the molecular potential energy surfaces, the masses of the atoms, and the associate coupling of vibrations of neighboring atoms in the molecule.

If the product of the chemical reaction is subjected to IR radiation and its absorption spectrum recorded and compared with the IR spectrum of the pure product recorded under similar conditions.If the spectra are superimposable shows that your product is pure and contains no reactant traces to make it impure.The bands in the fingerprint region are used for compound identification.

IR spectra of impure compound is blurred and contains many bands, which cannot be interpreted.