The document discusses pH, including its definition as the negative logarithm of the hydrogen ion concentration, its scale from 0-14, and methods of measuring it. pH is a measure of acidity or alkalinity and indicates whether a solution is acidic (pH less than 7), basic (pH greater than 7), or neutral (pH of 7). The key methods of measuring pH discussed are pH meters, pH strips, and pH indicators. Common applications of measuring pH include use in pharmaceutical, chemical, food production, and other industries.

1. pH
Garmian University
College of
education
Chemistry
department
analytical chemistry

2. Introduction
When weak acids or weak bases are dissolved in water they can contribute
H ionizing or consume H by being protonated. These processes are also
governed by equilibrium constant. The total hydrogen ion concentration
from all sources . Which is experimentally measurable, is expressed as the
pH of the solution
Water molecules have a slight tendency to undergo reversible ionization to
yield a hydrogen ion and a hydroxide ion
H20 → H+ + OH-
→

3. The concept of pH was first introduced by the Danish chemist
Sorenson in 1909.
P means ”puissance d” and H mean “hydrogen”, it is the French
word, which means strongth/power of hydrogen.
Defention : the formal defention of pH is the negative logarithm
of the hydrogen ion activity
pH = -log [H]
pH is a unit of measure which describe the degree of acidity or
alkanity (basic) of a solution .
It is measured on a scale of 0 to 14

4. The pH value of a substance is directly related to the ratio of the
hydrogen ion(H) and hydroxyl ion(OH) concentration
Lf the H” concentration is higher than OH the material is acidic
and the PH is less than (7)
Lf the OH concentration is higher than H” the material is
baseand the pH is more than (7)
Lf number of H” equals the number of OH” 7 is neutral isn’t
acidic isn’t base
pH value

5. . The ion product of water ,K is the basic for the pH scale
.the pH scale corresponds to the concentration of
hydrogen ions.
It is a convenient means of designating the actual
concentration of H”
.Sorenson ,used a logarithmic scale for expressing the H’
concentration this scale was called pH
The pH scale

7. pH meter
pH strips
pH indicator
Measurment of
pH

8. pH meter:
-the pH meter is a laboratory equipment which used to measure acidity or Base of
a solution .
-The pH meter measure the concentration of hydrogen ions(H) using an ion –
sensitive electrode
-It is the most reliable and convenient method for measuring pH.

9. pH strips
PH strips are pieces of paper that change color
depending on the pH the activity acid or base –
of a liquid
pH strips are brownish yellow in colour
(whatman filter );
By this method approx value is obtained,
which are less Aaccurate .

10. *pH indicators:
-indicators are the
organic compounds
of natural or
synthetic origin
whose colour
Is dependent on pH.
-the ph indicators
are either weak
acids or weak base
shaving different
colours in un
dissociated and
dissociated forms;

11. 1)pharmaceutical and chemical
industry
2)quality control
3)controlling of chemical reaction
4)food production
5)quality control at dairies
6)quality control and efficient
production in bakeries
7) agriculture, wastewater treatment,
industrial processes, environmental
monitoring, and in research and
development.
Application of pH :

12. THANK YOU