Question

The ir spectrum of benzilic acid is shown below. for each peak indicated by the blue boxes, select the bond represented by the frequency.

Answer 1

Below is the structure of Benzilic Acid and IR spectrum. First common thumb rule for elucidating IR spectrum is to find a broad and intense signal between 1690-1800 cm⁻¹, If present! Then its for Carbonyl group. Secondly, watch for broad peak around 3400-3600 cm⁻¹, peak at this frequency is given by the -OH (Hydroxyl) group of Alcohols, andthe broadness is due to Association effect (Hydrogen bonding). Third, aif a wide band between 2500-3300 cm⁻¹ is present it shown -OH of carboxylic acid.

Result:
           Carbony Group =  1640 cm⁻¹

          Carboxyl -OH Group  =  2950 cm⁻¹

          Alcohol -OH  =  3400 cm⁻¹