Describe how you could use IR spectroscopy to distinguish between ethyl acetate and butyric acid. The IR spectrum of butyric acid should have a broad signal between 1650 cm-1 and 1850 cm-1. An IR spectrum of ethyl acetate will not have this signal. The IR spectrum of butyric acid should have a broad signal between 2500 cm-1 and 3600 cm-1. An IR spectrum of ethyl acetate will not have this signal. The IR spectrum of ethyl acetate should have a broad signal between 2500 cm-1 and 3600 cm-1. An IR spectrum of butyric acid will not have this signal. The IR spectrum of ethyl acetate should have a broad signal between 1650 cm-1 and 1850 cm-1. An IR spectrum of butyric acid will not have this signal.