*Titrations

*Unit 3 Lecture 5

*Titrations
*Allow you to solve for the unknown

concentration of an acid or base using the principles of neutralization reactions

*Let’s stroll through Chem Honors
Memory Lane…

What are Titrations




The process of adding just enough acid or base to neutralize the solution
Remember that acids and bases react with each other to make a neutral salt solution.
• In the following examples, label the acid, base,

1.

and salt.
HCl(aq) + NaOH(aq)

(Acid)

2.



(Base)

Ca(OH)2(aq) + 2HNO3(aq) 
(Base)

(Acid)

H2O(l)
(Water)

+

NaCl(aq)
(Salt)

Ca(NO3)2(aq) + 2H2O(l)
(Salt)

(Water)

BIG IDEA I


To completely neutralize, the acid and base must react in the right ratio.

• What on earth does that mean?
Answer: We need the same amount of H+ ions and OHions in solution so they can form pure water (HOH).
• Why do we need the right amount?
Answer: Need [H+]= [OH-] to form pure water.
 Having more H+ ions leftover would make the solution more acidic  Having more OH- ions leftover would make the solution more basic.  Thus neither of the 2 solutions above would be neutralized.

BIG IDEA II


Finds concentrations of acids or bases that are unknown using math
• Huge for safety in a laboratory among

other uses

Indicators


Used as an acid/base detector during the experiment



Turns color based on what pH level it’s inside of



Many different indicators
• Why?

Answer: It depends on what type of acid and base are being added together.
 Strong acid with strong base neutralizes at a pH of 7
 Weak acid with a strong base neutralizes at a pH around 8.5.

*In Class Demo/ Example
Concentration of Known Soln

Volume of known concentration Volume of unknown soln

*So how is AP Chem
*Titrations can occur with:

different?

*Acid-base Reactions
*Precipitate Reactions
*Oxidation-Reduction Reactions
*We can