MEETING 5.
ACID-BASE TITRATION
- WHAT IS TITRATION?
- WHY ACID-BASE TITRATION IS CALLED
NEUTRALIZATION TITRATION?
- WHAT IS ACIDIMETRIC TITRATION?
- WHAT IS ALKALIMETRIC TITRATION?
- WHAT IS THE PRINCIPLE OF REACTION?
Titration
Strong
acid
Weak
acid
Strong
base
Weak
base
Principle reaction:






Involve the change of [H+] and [OH-]
Involve the change of pH.
What is pH?
What is pH of 100 mL HCl 0,1 M?
What is pH of 100 mL NaOH 0,1 M?
Is pH of 100 mL HCl 0,1 M similar with pH of 100
mL CH3COOH 0,1 M
Curve of Acid-base Titration
HCl + NaOH  NaCl +
H2O
Reaksi ionnya :
H+ + OH- 
H2O
Strong acid + Strong Base
Example:
HCl + NaOH  NaCl + H2O
Ionic reaction:
H+ + OH-  H2O
What is the pH of titration?
10 mL HCl 0,1 M + 0 mL NaOH ?
 10 mL HCl 0,1 M + 5 mL NaOH 0,1 M?
 10 mL HCl 0,1 M + 10 mL NaOH 0,1 M?
 10 mL HCl 0,1 M + 20 mL NaOH 0,1 M?

HOW ABOUT THIS?
10 mL HCl 0,1 M + 0 mL NH4OH ?
10 mL HCl 0,1 M + 5 mL NH4OH 0,1 M?
10 mL HCl 0,1 M + 10 mL NH4OH 0,1 M?
10 mL HCl 0,1 M + 20 mL NH4OH 0,1 M?
Indicator in Acid-base titration
The color change should be as near as
possible to equivalent point
 In Fact: it is very difficult
end point
of titration
 End Point ~ Equivalent Point
 How can we choose the indicator?

pH range of some indicators
Indikator
Daerah
pH
Warna
asam
Warna
basa
Pelarut
Thimol biru
1,2 - 2,8
Merah
Kuning
Air
Metil kuning
2,9 – 4,0
Merah
Kuning
Etanol
95%
Metil jingga
3,1 – 4,4
Merah
Kuning
jingga
Air
Metil merah
4,2 – 6,2
Merah
Kuning
Air
Bromtimol biru
6,0 – 7,6
Kuning
Biru
Air
Phenolphtalein
8,0 – 9,8
Tak
berwarna
Merahungu
Etanol
70%
Example:
Contoh Perubahan Warna
The color
change of Acid-Base Indicator
Indikator
Asam-basa
Universal Indicator