Question

Carboxylic acids have higher than expected boiling points due to dimeric associations involving hydrogen bonding. Several dimers of 3‑methylbutanoic acid (3‑methylbutyric acid) are shown where proposed hydrogen bonding is represented by a dotted line.

Select the pair of compounds that show all of the expected hydrogen bonds in a carboxylic acid dimer.

CH C HzCº. ---- H_CH, T 0 O= CH3

Answer 1

TV th structure is correct structure st o la CH-CH3 н oso oso 1413 CH3 s-, H₃ C CHg Dimer formation Shung Hyllogen Benuing exkst blw and H of alwho 1 carbonyl oxygen In other structures Incomplete H- Bonding is shown so 4th Shuuuu is accurate. In 4th structure → Hydrogen Bond is forming b/w tally changed Harom and lone pair on fairly Negattue Oxygen atom.