1. Chapter 4.8 Review
Acid-Base Reactions

2. Acid-Base Reactions Reminder: Arrhenius (irrelevant) acids/bases
Brønsted-Lowry acids/bases (protons only): Acids are proton donors, bases are proton acceptors
Acid-Base Reactions are called neutralization reactions because the acid/base becomes neutralized by the base/acid added to it.
*OH- will react with both strong and weak acids
acid + base salt + water

3. Example
What volume of a M HCl solution is needed to neutralize 25.0 mL of M NaOH?
Write out reaction: HCl + NaOH --> NaCl + H2O
0.250L X 0.350mol NaOH X 1mol HCl X __1L HCl_
1 L mol NaOH mol HCl
Solve for = L of hydrochloric acid needed

4. Titrations!
If we know the concentration and amount of either the acid or base (titrant in the buret), we can determine the concentration of the other (base or acid) by adding the titrant until the reaction is neutralized (equivalence point)

5. Titration Setup
An indicator is added to the solution to be analyzed (usually phenolpthalein is added to the acid). It will indicate when the solution is one drop beyond a specific pH (phenolpthalein is 7). This is called the endpoint.
Endpoint is where the color changes vs. equivalence point, where the number of moles of acid = moles of base
Video

7. Titration Steps
Record initial volume of the known concentration of base/acid in buret
Record amount (usually mL) of unknown concentration acid/base in beaker
Add a few drops of indicator to beaker
Add titrant until the indicator has just permanently changed color
Record the final volume of the known concentration of base/acid in buret
You will now have the information needed to calculate the concentration of the unknown

8. Example
Use the following data to calculate the concentration of the HCl solution:
HCl in beaker with indicator: 10.4mL
Initial buret reading: 3.5mL 0.100M NaOH
Final buret reading (pink): 15.4mL 0.100M NaOH
**write out the reaction first!!
Answer: 0.114M HCl

9. Book Example More complicated problem on page 159
TIP pg. 160: The first step in the analysis of a complex solution is to write down the components and focus on the chemistry of each one. When a strong electrolyte is present, write it as separated ions.