Question

The 1H NMR spectrum of an unknown acid has the following peaks: δ (ppm) = 12.71 (1H, s), 8.04 (2H, d), 7.30 (2H, d), 2.41 (3H, s) Which structure best fits this spectral information?

Answer 1

Answer:

The most appropriate structure given the sparse spectral data is 4-acetyl benzoic acid (see attached).

Explanation:

It is difficult to accurately elucidate the structure of this compound without its chemical formula. But from the 1H NMR spectral data shows a total of 8 hydrogen atoms:

1. 12.71 (1H. s) -  confirms presence of carboxylic acid proton, C=O-OH
2. 8.04 (2H, d) - confirms aromatic hydrogen
3. 7.30 (2H, d) - confirms aromatic hydrogen
4. 2.41 (3H,s) - confirms C=C hydrogen or ketone O=C-RCH3

The attached files show the structure and the neighboring hydrogen atoms.

The most likely structure i 4-acetyl benzoic acid