C. Johannesson III. Titration/Neutralization 18.4 Ch. 18- Acids & Bases

A. Neutralization HCl + NaOH → NaCl + H 2 O -Chemical reaction between an acid and a base. -Neutralization reactions ALWAYS produce a salt (which is an ionic compound) and water. -Of course, it takes the right proportion of acid and base to produce a neutral salt

C. Johannesson A. Neutralization ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H 2 O HC 2 H 3 O 2 + NaOH  NaC 2 H 3 O 2 + H 2 O Salts can be neutral, acidic, or basic. Neutralization does not mean pH = 7. weak strong neutral basic

C. Johannesson B. Titration  Titration Analytical method in which a standard solution is used to determine the concentration of an unknown solution. standard solution unknown solution

C. Johannesson  Equivalence point Point at which equal amounts of H 3 O + and OH - have been added. B. Titration

C. Johannesson  Equivalence point Determined by… indicator color change –phenolpthalein turns hot pink in a base B. Titration

C. Johannesson  Equivalence point Determined by… dramatic change in pH B. Titration

B. Titration and Neutralization  The solution of known concentration is called the standard solution added by using a buret  Continue adding until the indicator changes color called the “end point” of the titration end points are different for different indicators

B. Titration Steps 1. A measured volume of acid of known concentration is added to a flask 2. Several drops of an indicator are added 3. A base of unknown concentration is slowly added and swirled until the indicator changes color; measure the volume delivered by the buret

B. Titration Process C. Johannesson

B. Titration moles H 3 O + = moles OH - M  V  n = M  V  n M:Molarity V:volume n:# of H + ions in the acid or OH - ions in the base

C. Johannesson B. Titration  42.5 mL of 1.3M KOH are required to neutralize 50.0 mL of H 2 SO 4. Find the molarity of H 2 SO 4. H3O+H3O+ M = ? V = 50.0 mL n = 2 OH - M = 1.3M V = 42.5 mL n = 1 MV# = MV# M(50.0mL)(2) =(1.3M)(42.5mL)(1) M = 0.55M H 2 SO 4

Worksheet  Complete the worksheets on titration C. Johannesson