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.

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.

Explanation:

IR spectroscopy is a widely used technique in chemical identifications. In a IR spectrum, signals depend of nature of bonds in the chemical structure of the compound.

Ethyl acetate is an esther. Its principal signal is between 16500cm⁻¹ and 1850cm⁻¹ (Carboxylic compound).

Butyric acid is a carboxylic acid. Carboxylic acids have 2 principal signals: The first is between 16500cm⁻¹ and 1850cm⁻¹ (Carboxylic compound) and the second is between 2500cm⁻¹ and 3600cm⁻¹ (Due the hydrogen bonding between O-H atoms).

Thus, right answer is:

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.