The acid shown has $p K_{a} = 4.76$ . Which of the structures A to D is the strongest acid?

AStructure A
BStructure B
CStructure C
DStructure D

Answer: B

The reference is ethanoic (acetic) acid. Each additional chlorine on the alpha carbon exerts a -I effect and stabilises the carboxylate: pKa 4.76, 2.86, 1.29, 0.65. Hence trichloroethanoic acid is the strongest.

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The acid shown has pKa​=4.76. Which of the structures A to D is the strongest acid?

Answer: B

More questions on Acidity order and derivative reactivity among drawn carboxylic acids

The acid shown has $p K_{a} = 4.76$ . Which of the structures A to D is the strongest acid?