Question

Compare the relative acidities of ethanoic acid, propanoic acid, fluoroethanoic acid and iodoethanoic acid. Explain your answer giving appropriate answers.

Answer 1

Ethanoic acid: pKa = 4.76

Propanoic acid: pKa = 4.87

Fluoroethanoic acid: pKa = ‎2.59

Iodoethanoic acid: pKa = 3.18

So, the most acidic is the fluoroethanoic acid, then iodoethanoic acid, then ethanoic acid, and the last one is propanoic acid.