Slide show of the topic Acid & Base as a part of the assignment in our Physical Chemistry course. Created by: Annisa Hayatunnufus Bachelor of Pharmacy Management & Science University

1. A
B
ACID & BASE
Annisa Hayatunnufus
Bachelor of Pharmacy
For Subject Physical Chemistry

2. GENERAL
DEFINITION THEORIES
CHARACTERISTICS
CLASSIFICATION
DEFINITION
INDICATOR &
MEASURING TOOLS
DISSOCIATION
CONSTANT
ACID & BASE EQUILIBRIUM
CONSTANT
pH CALCULATION

3. B
A. Acid & Base (Introduction)
 Ionic compounds (a
compound with a
positive/negative
charge) that break
apart in water to form a
hydrogen ion (H+).
 Strength proportional
to concentration of
H+ ions in the solution.
 Ionic compounds that
break apart to form a
negatively charged
hydroxide ion (OH-) in
water.
 Strength proportional to
concentration of
Hydroxide ions (OH-).
 Solutions containing
bases are often
called alkaline.

4. B
A. Acid & Base (Introduction)
THEORIES
Brønsted-
lowry
LewisArrhenius

5. B
A. Acid & Base (Introduction)
ACIDS BASES
Sour Bitter
Change color of litmus
paper to red
Change color of litmus
paper to blue
One of composer of many
food and beverages (ie.
vinegar, cheese, fruits)
In normal state present in
a form of solid crystal and
the strong ones are caustic
React with certain metals
to produce gaseous H2
Feel slippery
React with bases to form
salt & water
React with acids to form
salt & water

6. B
CLASSIFICATION
A. Acid & Base (Introduction)
From its origin
Organic Acid
Generally weak
acids,
corrosive, and
abundant in
nature
Anorganic Acid
Generally
strong acids,
corrosive, and
human-made

7. B
CLASSIFICATION
A. Acid & Base (Introduction)
From amount of proton given
Monoprotic
Donates only
one proton
or hydrogen
atom per
molecule: HCl,
HNO3
Polyprotic
Donates more
than
one proton
or hydrogen
atom per
molecule: H2S,
H2SO4, H3PO4
• H2S  HS-  S2-
• H3PO4  H2PO4
-  HPO4
2-  PO4
3-
Example:

8. B
CLASSIFICATION
A. Acid & Base (Introduction)
From its strength From its strength
Strong Acid
Completely
ionized in
solution. There
are only 7
strong acids:
HCl, HBr, HI,
H2SO4, HNO3,
HClO3, HClO4
Strong Base
Completely
ionized too with
only 8
members:
LiOH, NaOH,
KOH, RbOH,
CsOH, Ca(OH)2,
Sr(OH)2, Ba(OH)2
Weak Acid
Not completely
ionized in
solution.
Examples are
all acids aside
from the ones
mentioned
before.
Weak Base
Also not
completely
ionized.
Examples are
all acids aside
from the ones
mentioned
before.

9. B
CLASSIFICATION
A. Acid & Base (Introduction)
From its origin
Organic Acid
Generally weak
acids,
corrosive, and
abundant in
nature
Anorganic Acid
Generally
strong acids,
corrosive, and
human-made
From its strength From its strength
Strong Acid
Completely
ionized in
solution. There
are only 7
strong acids:
HCl, HBr, HI,
H2SO4, HNO3,
HClO3, HClO4
Strong Base
Completely
ionized too with
only 8
members:
LiOH, NaOH,
KOH, RbOH,
CsOH, Ca(OH)2,
Sr(OH)2, Ba(OH)2
Weak Acid
Not completely
ionized in
solution.
Examples are
all acids aside
from the ones
mentioned
before.
Weak Base
Also not
completely
ionized.
Examples are
all acids aside
from the ones
mentioned
before.
Example:

10. A
B. pH Measure of Acidity
 The strength of an acid or base in an aqueous solution is
measured on a scale called a pH scale.
 The pH scale is a measure of the hydrogen ion concentration. It
spans from 0 to 14 with the middle point (pH 7) being neutral
(neither acidic or basic).
 Any pH number greater than 7 is considered a base and
any pH number less than 7 is considered an acid.
 0 is the strongest acid and 14 is the strongest base.
pH?

11. A
B. pH Measure of Acidity
INDICATOR & MEASURING TOOLS
Indicator
Low pH
color
High pH
color
Hydrangea
flowers
blue
pink to
purple
Anthocyanins red blue
Litmus red blue
Universal Indicator Solution Low pH color pH range High pH color
Thymol blue (first transition) Red 1.2 – 2.8 Yellow
Methyl red Red 4.4 – 6.2 Yellow
Bromothymol blue Yellow 6.0 – 7.6 Blue
Phenolphthalein Colorless
8.3 –
10.0
Fuchsia
pH Meter

12. A
B. pH Measure of Acidity
Dissociation Constant (Kw)
Can also be known as ion product of
water. Water dissociation is one of
the most fundamental acid-base
reaction
In this reaction, water breaks apart
to form a hydrogen ion (H+) and a
hydroxide ion (OH-). In pure water,
we can define a special equilibrium
constant (Kw) as follows:
H2O H+ + OH-
KW = [H+][OH-] = 1.00x10-14

13. A
B. pH Measure of Acidity
The equilibrium constants (Ka & Kb)
HA + H2O → H3O+ + A– A− + H2O → HA + OH–
• The strength of an acid HA
in water can be defined by
the equilibrium:
• Similarly, the strength of the
base A– in water is defined
by the equilibrium:
How are Ka and Kb related? The answer can found by
multiplying the above two expressions for Ka and Kb:
∴ Ka Kb = Kw

14. A
B. pH Measure of Acidity
The equilibrium constants (Ka & Kb)
HA + H2O → H3O+ + A– A− + H2O → HA + OH–
• The strength of an acid HA
in water can be defined by
the equilibrium:
• Similarly, the strength of the
base A– in water is defined
by the equilibrium:
How are Ka and Kb related? The answer can found by
multiplying the above two expressions for Ka and Kb:
∴ Ka Kb = Kw
As the strength of
a series of acids
increases, the
strengths of their
conjugate bases
will decrease
• Kw, Ka, & Kb are needed in calculating reactions that involve weak acid/base
(ex: buffer solutions & hydrolisis of salt)
• Buffer solutions:
• contains a weak acid (ex: CH₃COOH) together with a salt of the acid
(ex: CH₃COONa)
• used to resists a change in its pH when H+ or OH– ions are added or
removed.
• usage ex.: Blood is strongly buffered (mainly by bicarbonate) to
maintain its pH at 7.4±0.3; pH values below 7.0 or above 7.8 cause
death within minutes.
• Hydrolisis of Salt:
• dissolved salts that derives from weak acid & weak base may cause an
increase or decrease of pH according to the Ka & Kb value of the salt.
• when Ka > Kb, solution will be more acidic. When Ka < Kb, solution will
be more alkaline.

15. A
B. pH Measure of Acidity
Calculating pH
• pKb = - log (Kb)
• Kb = 10-pKb
• Kb = antilog ( - pKb)
• pKa = - log (Ka)
• Ka = 10-pKa
• Ka = antilog ( - pKa)
• pOH = - log [OH-]
• [OH-] = 10-pOH
• [OH-] = antilog ( -
pOH)
• -log [H+]
• [H+] = 10-pH
• [H+] = antilog ( - pH)
[H+] [OH-]
KbKa
pH + pOH = 14

16. Content References
• Lower, Stephen. Introduction to Acid-base Chemistry. Chem1 General Chemistry
Reference Text [Online] 1999. Available from:
http://www3.imperial.ac.uk/library/subjectsandsupport/referencemanagement/van
couver/references [Accessed 10th November 2014]
• Bogren, Sue & Urbana Middle School Teachers. Acid, Base, and pH Tutorial.
[Online]. Available from:
http://lrs.ed.uiuc.edu/students/erlinger/water/background/ph.html [Accessed 10th
November 2014]
• Gunawan, Ary. BAB 2. ASAM, BASA, DAN GARAM. United Science. Weblog.
[Online] Available from: http://unitedscience.wordpress.com/ipa-1/bab-2-asam-
basa-dan-garam/ [Accessed 10th November 2014]
• UNKOWN. Pengertian Asam Basa. Alfikimia. Weblog. [Online] Available from:
http://alfikimia.wordpress.com/kelas-xi/larutan-asam-basa/a-pengertian-asam-
basa/ [Accessed 10th November 2014]
• Shodor Organization. Acid-Base Chemistry. [Online]. Available from:
http://www.shodor.org/unchem/basic/ab/ [Accessed 10th November 2014].
• http://depts.washington.edu/chemcrs/bulkdisk/chem142A_win07/notes_Solutions
_Chapter_07.pdf [Accessed 15th November 2014]
Pictures not included