Sulfuric acid provides the highest [H+] due to being diprotic. Steps: - Classify acids: butanoic (A) and ethanoic (B) are weak monoprotic; hydrochloric (C) is strong monoprotic; sulfuric (D) is strong diprotic. - Calculate [H+] for weak acids: partial dissociation (Ka ~10^{-5}), so [H+] ≈ √(Ka × 0.01) ≈ 10^{-3} M, pH ≈ 3. - For HCl: full dissociation, [H+] = 0.01 M, pH = 2. - For H2SO4: first H+ fully dissociates ([H+] = 0.01 M), second mostly dissociates (Ka2 = 10^{-2}), total [H+] ≈ 0.019 M, pH ≈ 1.7. Why D is correct: - As a strong diprotic acid, H2SO4 releases ~2 H+ per molecule (via H2SO4 → H+ + HSO4-, then HSO4- ⇌ H+ + SO4^2-), yielding highest [H+] by Le Chatelier's principle at dilute concentrations. Why the others are wrong: - A: Weak acid, low dissociation, [H+] < 0.01 M, pH > 2. - B: Weak acid (similar to A but slightly weaker Ka), low dissociation, pH > 2. - C: Strong monoprotic acid, [H+] = 0.01 M, pH = 2 > D's pH. Final answer: …