Acid/Base Chemistry Part II

1. Acid/Base Chemistry Part II CHEM 2124 – General Chemistry II Alfred State College Professor Bensley

2. Learning Objectives • Write the chemical equation for a weak acid undergoing acid ionization in aqueous solution. • Define acid dissociation constant. • Determine Ka from a solution pH. • Calculate concentrations of species in a weak acid solution using Ka. • Write the hydrolysis reaction of an ion to form an acidic solution.

3. Learning Objectives • Recognize common acid-base reactions. • Predict whether a salt solution is acidic, basic, or neutral. • Calculate concentrations of acid or base solutions through titrations. • Define buffer.

4. Learning Objectives • Describe the pH change of a buffer solution with the addition of an acid or a base. • Calculate the pH of a buffer from given volumes of solution. • Calculate the pH of a buffer when a strong acid or a strong base is added. • Learn and apply the Henderson-Hasselbalch equation.

5. Acid/Base Chemistry – Part II A. Equilibrium and Acid Dissociation Constants

6. Acid/Base Chemistry – Part II B. The relationship between [H3O+], pH, and Ka [H3O+] = √KaC0 pH = ½ pKa – ½ log C0

7. Acid/Base Chemistry – Part II C. Common Acid/Base Reactions 1. Neutralization reaction 2. Net Ionic Reaction of Neutralization reactions: 3. Bicarbonate Base reactions D. The Acidity and Basicity of Salt Solutions NaHCO3 NaCl Na+ from NaOH strong base HCO3− from H2CO3 weak acid Na+ from NaOH strong base Cl− from HCl strong acid

8. NH4Cl NH4+ from NH3 weak base Cl− from HCl strong acid

9. E. Buffers Acid/Base Chemistry – Part II A buffer is a solution whose pH changes very little when acid or base is added.

10. Acid/Base Chemistry – Part II F. Calculating the pH of a Buffer Henderson-Hasselbalch Equation • pH = pKa + log ([A-]/[HA]) • pH = pKa + log Cs – log Ca