JEE MAIN - Chemistry (2005 - No. 52)
Among the following acids which has the lowest pKa value?
CH3COOH
HCOOH
(CH3)2COOH
CH3CH2COOH
Explication
$$p{K_a} = - \log \,{K_a};\,\,HCOOH\,\,$$ is the strongest acid and hence it has the highest $${K_a}$$ or lowest $$p{K_a}$$ value.