Question
Chemistry Question on Aldehydes, Ketones and Carboxylic Acids
Which one of the following have lowest pKa?
A
ClCH2CH2COOH
B
Cl2CHCH2COOH
C
ClCH2COOH
D
Cl2CHCOOH
Answer
Cl2CHCOOH
Explanation
Solution
Chlorine has the highest - I effect at the a position. Since ClCH2COOH has only one α−Cl atom and Cl2CHCOOH has two α−Cl atoms; therefore, CHCl2COOH is a strongest acid among all and has lowest pKa value.