Weak vs strong acid
Weak vs strong acid is an interactive experiment in pH & Titration, a free simulation from StudyFi Lab that runs right in your browser.
Both beakers hold 25 mL of acid at 0.1 mol/L. HCl is fully dissociated, CH₃COOH only slightly (Ka = 1.8·10⁻⁵), so it starts at a higher pH. During the titration acetic acid turns into acetate and the mixture acts as a buffer: pH = pKa + log([A⁻]/[HA]). At half-equivalence [A⁻] = [HA], so pH = pKa ≈ 4.74.
Try this: Choose CH₃COOH and add exactly 12.5 mL of NaOH. Read the pH and compare it with pKa. Then try the same with HCl.
Frequently asked questions
What does the “Weak vs strong acid” experiment show?
Both beakers hold 25 mL of acid at 0.1 mol/L. HCl is fully dissociated, CH₃COOH only slightly (Ka = 1.8·10⁻⁵), so it starts at a higher pH. During the titration acetic acid turns into acetate and the mixture acts as a buffer: pH = pKa + log([A⁻]/[HA]). At half-equivalence [A⁻] = [HA], so pH = pKa ≈ 4.74.
How do I try “Weak vs strong acid”?
Choose CH₃COOH and add exactly 12.5 mL of NaOH. Read the pH and compare it with pKa. Then try the same with HCl.
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