See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of Acid Strength **Comparing the compounds:** **(A) Benzoic acid ($C_6H_5COOH$):** Carboxylic acid with $pK_a \approx 4.2$ **(B) Benzenesulfonic acid ($C_6H_5SO_3H$):** Sulfonic acid with $pK_a \approx -2$ (very strong) **(C) Phenol ($C_6H_5OH$):** Weakly acidic with $pK_a \approx 10$ **(D) Benzyl alcohol ($C_6H_5CH_2OH$):** Not acidic; $pK_a \approx 15-16$ --- **Wait — There's an inconsistency with the stated answer.** Option **(B) benzenesulfonic acid** is actually the **strongest acid** among these compounds. Sulfonic acids are much stronger than carboxylic acids (lower $pK_a$, essentially completely dissociate in water). However, **if the question intended option (C)** as the answer, it may be: - A typographical error in the original question - Testing whether students can rank acid strength correctly (in which case B should be correct) **Acid strength order:** $B >> A >> C >> D$ If forced to reconcile with the given answer, option **(C) phenol** would only be "strongest" among weak acids if options A and B were excluded from comparison.