2. Presentation submitted by:
Shoaib Saikat
Roll no: 18 BIO 013
Antar Ranjan Karmakar
Roll no: 19 BIO 001
Anup Roy
Roll no: 19 BIO 004
Presentation submitted to:
Md. Hasib
Lecturer
Department of Biochemistry and
Biotechnology,
University Of Barisal
Topic: Acid Base Titration and Suitable
Indicators
4. Titration technique a solution of known concentration
Determine the concentration of an unknown solution
Titration
Titrant
Titrand
Acid – Base titration method of quantitative analysis determining
the concentration of an acid or base neutralizing it with a standard
solution of base or acid known concentration
Acid – Base Titration
5. PRINCIPLE
Acid
Acid + Base = Salt + Water
Base
01
02
03
𝑝𝐻 𝐶ℎ𝑎𝑛𝑔𝑒
𝐼𝑛𝑑𝑖𝑐𝑎𝑡𝑜𝑟
↓
𝑝𝐻 7 𝑁𝑒𝑢𝑡𝑟𝑎𝑙
↓
𝐶𝑜𝑙𝑜𝑟 𝑐ℎ𝑎𝑛𝑔𝑒
Nutralization Reaction
6. Example of A Neutralization Reaction
𝐻𝐶𝑙(𝑎𝑞) + 𝑁𝑎𝑂𝐻(𝑎𝑞) → 𝑁𝑎𝐶𝑙(𝑎𝑞) + 𝐻2𝑂(𝑙)
NaOH
HCl → 𝐻+ + 𝐶𝑙−
→ 𝑁𝑎+ + 𝑂𝐻−
NaOH
HCl + →
NaOH
HCl +
15. Case – 1: Strong Acid – Strong Base
HIn
𝐼𝑛−
Ionized Non-ionized
Methyl
Red
Start Point End Point
HIn
𝐼𝑛−
Ionized Non-ionized
Cresol Red
Start Point End Point
All Indicators are suitable
16. Case – 2: Strong Acid – Weak Base
HIn
𝐼𝑛−
Ionized Non-ionized
Methyl Red
Start Point End Point
17. Case – 3: Weak Acid – Strong Base
HIn
𝐼𝑛−
Ionized Non-ionized
Start Point End Point
Cresol Red
18. Case – 4: Weak Acid – Weak Base
Weak Acid Weak Base
No Suitable Indicators
pH Change
↓
Too Gradual
19. Titration Curve of a Strong Acid – Strong Base
The regions over which the
indicators methyl red and
phenolphthalein change
color
along the steep portion of
thecurve, they can be used
to
monitor the equivalence
point ofthe titration.
Thymol blue, on theother
hand, cannot be used
forthe same purpose
because thecolor change
does not match thesteep
portion of the titration
curve
20. The pH range the indicator changes the acid color to the base color
21. Chemists use indicators in their analytical work to test substances for their acidity.Also to know the point
when an acid neutralises a base.
Indicators are used in soil testing. The soil can be slightly acidic or basic. To usean indicator, moisten the soil
with a little bit of water and add universal indicator(UI). Then place some white barium sulfate powder on the
surface of the soil. Thewhite power absorbs the soil water and the indicator colour can be seen against the
white background. Excess soil acidity can be fixed by adding basic substances such as lime.
Indicators are used to measure the acidity of water in a swimming pool. If the water is too acidic, it will cause
irritations to the eyes and skin. If the water is too basic, green algal scum will grow in the pool.
Indicators are used in waste water monitoring. Ensuring alkaline solutions are neutralised before discharged
into sewer.
Indicators are used in testing water in aquariums. Fish are sensitive to the pH of water so it must be
controlled and maintained.
Acid-Base indicators In Everyday uses:
Editor's Notes
THOSE SUBSTANCES THAT PRODUCE
ARE substances WHOSE solutions change color DUE TO changes in pH
IS A------------FOR---------------BY---------------OF
IF WE ADD ACID AND BASE TOGETHER THEY NEUTRILIZE EACH OTHER BY REACTION AND PRODUCE SALT AND WATER. THIS REACTION IS CALLED NEUTRILIZATION REACTION
NOW IN CASE IF WE HAVE USED INDICATOR IN THE ACID OR IN THE BASE, THE COLOR WOULD CHANGE AS THE pH CHANGES TO 7 WHICH IS NEUTRAL PH