A chemist would like to monitor the progress of a chemical reaction using UV/V is spectroscopy. The spectrum for the starting material (solid line) and the product (dashed line) are given. At what wavelength should the chemist set the detector to monitor the course of the reaction? Explain your answer.

Absorbance 0.8 0.6 0.4 0.2 200 voll 300 400 500 600 Starting Material Product 700 800