Question: Tell how IR spectroscopy could be used to determine when each reaction is complete.

IR refers to the infrared region which deals with frequencies and absorbance. The product can be identified on the basis of change in the IR frequency.

a. The loss of the C=C will be visible in the IR by the disappearance of the peak at 1650 cm^-1

Reaction a

b. The loss of the O–H group will be visible in the IR by the disappearance of the peak at 3200–3600 ${\mathrm{cm}}^{-1}$and the appearance of the C=O at 1700 ${\mathrm{cm}}^{-1}$.

Reaction b

c. The loss of the C=C will be visible in the IR by the disappearance of the peak at 1650 ${\mathrm{cm}}^{-1}$and the appearance of the C=O at 1700 ${\mathrm{cm}}^{-1}$.

Reaction c

d. The loss of the O–H will be visible in the IR by the disappearance of the peak at 3200–3600 cm^-1.

Reaction d