Question

The correct order of the decreasing pK\textsubscript{a} values of the compounds is

• A. I>II>III>IV
• B. II>I>III>IV

Answer 1

Answer: (B)

II > I > III > IV

Answer 2

The pKa values are approximately:

• Methanol (II): pKa ≈ 16

• Phenol (I): pKa ≈ 10

• Benzoic acid (III): pKa ≈ 4.2

• Formic acid (IV): pKa ≈ 3.75

Since a lower pKa indicates a stronger acid, the order from the highest pKa (weak acid) to the lowest pKa (strong acid) is: Methanol (II) > Phenol (I) > Benzoic acid (III) > Formic acid (IV)