Question

Among the following acids which has the lowest $p{K}_a$ value?

• A. $C{H}_{3}COOH$
• B. $HCOOH$
• C. $(C{H}_3{)}_{2}CHCOOH$
• D. $C{H}_{3}C{H}_{2}COOH$

Answer 1

The correct option is B $HCOOH$

HCOOH is strongest acid and hence has highest $K_a$​ value and lowest $p{K}_a$ value.