Describe how IR spectroscopy might be used to monitor the progress of each of the following reactions. Select all that apply. H2 Ni a Appearance of a C=C signal -1600 cm 1. Appearance of a broad signal between 3200 and 3600 cm-1. Disappearance of a signal -3100 cm-1. Shifting of the signal -1700 cm-1 to a higher wavenumber. Shifting of the signal -1700 cm 1 to a lower wavenumber. Appearance of a signal ~3100 cm-1 Disappearance of a C=C signal -1600 cm-1 Disappearance of a broad signal between 3200 and 3600 cm 1