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

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

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.

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.

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

B. The relationship between [H 3 O + ], pH, and K a [H 3 O + ] = √K a C 0 pH = ½ pK a – ½ log C 0 Acid/Base Chemistry – Part II

1. Neutralization reaction C. Common Acid/Base Reactions 2. Net Ionic Reaction of Neutralization reactions: 3. Bicarbonate Base reactions D. The Acidity and Basicity of Salt Solutions NaCl Na + from NaOH strong base Cl − from HCl strong acid NaHCO 3 Na + from NaOH strong base HCO 3 − from H 2 CO 3 weak acid

NH 4 Cl NH 4 + from NH 3 weak base Cl − from HCl strong acid

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

F. Calculating the pH of a Buffer Henderson-Hasselbalch Equation pH = pK a + log ([A - ]/[HA]) pH = pK a + log C s – log C a