1. Acid-Base Titration & pH Chapter 15A
West Valley High School
General Chemistry
Mr. Mata

2. Essential Question:
How is titration used to determine the molarity of an unknown acid or base?

3. Acid – Base Titration
Titration = method to determine the concentration of an unknown acid or base.
Standard solution = solution of known concentration (molarity).
Endpoint = point at which neutralization occurs.
Endpoint usually shown by color change of an acid-base indicator.

4. Indicators Indicators
compounds that change their molecular configuration in the presence of acids or bases.
Indicators appear to change color when placed in different concentrations of acids and bases.
Phenolphthalein
colorless in the presence of an acid and magenta in the presence of a base.
Universal Indicator
displays a spectrum of colors, depending upon acid and base concentration.

5. Indicator Use
Some indicators are better suited to different acid/base reactions.
Transition interval
the range of pH that they are effective.
End point
point where indicator changes from one color to another.
mole H+ = moles OH- (endpoint = 7)

6. Titrations
Titrations allow us to analytically determine an acid or base concentration (M).
Titrations are far more precise than indicators.
Titrations are performed by adding a known amount of a known-concentration acid to an unknown base or…
Adding a known amount of a known-concentration base to an unknown acid.

7. Titration Curves
Titration curves can show how pH of a titration (acid-base solution) changes as one compound is added to the other.
The equivalence point is the point at which:
mole acid = mole base

8. Buret Used in Acid-Base Titrations