Question

The pKa value is equivalent to ________

(a) logKa

(b) -logKa

(c) logKeq

(d) -logKeq

This question was posed to me in an internship interview.

The question is from Carboxylic Acids Chemical Reactions topic in section Aldehydes, Ketones and Carboxylic Acids of Chemistry – Class 12

Answer 1

Correct answer is (b) -logKa

To explain: Keq is the equilibrium constant of a reaction and Ka is the acid dissociation constant which is Keq[H2O]. The strength of an acid is generally by its pKa value rather than its Ka value.