Question

Rank the following compounds from strongest to weakest acid.

a. CH₃CO₂H
b. CH₃CH₂OH
c. CF₃CH₂OH
d. CF₃CO₂H

Answer 1

The compounds can be ranked based on the strength of their conjugate bases. CF₃CO₂H is the strongest acid, followed by CH₃CO₂H, CF₃CH₂OH, and CH₃CH₂OH.

Step-by-step explanation:

The compounds can be ranked in order of increasing acidity by considering the strength of the conjugate base.

1. CF₃CO₂H - This compound is a carboxylic acid, and its conjugate base would be CF₃CO₂⁻. The electron-withdrawing trifluoromethyl groups stabilize the negative charge on the conjugate base, making it more stable and therefore a weaker base, leading to a stronger acid.
2. CH₃CO₂H - This compound is also a carboxylic acid, but it has a less electron-withdrawing methyl group. The conjugate base, CH₃CO₂⁻, is therefore less stable, making it a stronger base and the acid weaker than CF₃CO₂H.
3. CH₃CH₂OH - This compound is ethanol, which is a weak acid. The conjugate base, CH₃CH₂O⁻, is not very stable due to the lack of electron-withdrawing groups, making the acid weaker than the others.
4. CF₃CH₂OH - This compound, known as trifluoroethanol, has more electron-withdrawing trifluoromethyl groups than ethanol. The conjugate base, CF₃CH₂O⁻, is therefore less stable, making the acid stronger than ethanol, but weaker than CF₃CO₂H and CH₃CO₂H.