GROUP TWO CHEMISTRY
PRESENTATION
THE pH SCALE
GROUP MEMBERS
Ayeni Araoluwanimi
Ayilaran Oloruntoni
Micheal Philip
Akinwande Iyanuoluwa
Ogualu Victor
Oyetunji Nehemiah
Atoki Donald
STUDY OUTLINE
History of the pH scale
The meaning of pH
The meaning of the pH scale
Nature of the pH scale
Reasons for the development of the pH
scale
Importance of the pH scale
LET’S DIVE IN
HISTORY OF pH AND THE pH SCALE
Søren Peder Lauritz Sørensen (Jan 9 1868-Feb 12 1939), a
Danish biochemist and director of the research laboratories
at Carlsberg Breweries (now Carlsberg Group), published his
work defining pH as the negative logarithm of the hydrogen
ion concentration. He recognized that hydrogen ion
concentration played a crucial role in enzymatic reactions
and wanted a simple way to express it.
Sørensen was working at the Carlsberg Laboratory in
Copenhagen, Denmark, where he was studying proteins
and noticed the impact of hydrogen ion concentration on
their behavior.
And in 1909, he successfully invented the logarithmic pH scale
THE pH SCALE
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
ACIDIC NEUTRAL ALKALINE
What is pH ?
The full meaning of pH is “potential of
hydrogen”
Lauritz Sorenson, the developer of the pH
scale, defined pH as the “negative logarithm
of the hydrogen ion concentration to base
10”.
It is also defined the concentration of
hydrogen ions in a solution
pH is a measure of the acidity or basicity of a
solution, specifically its hydrogen ion
concentration.
What is the pH scale?
The pH scale is a way to measure how acidic
or basic a solution is, ranging from 0 to 14.
Values below 7 indicate acidity, while values
above 7 indicate alkalinity (basicity). A pH of
7 is considered neutral, like pure water.
The pH scale is a numerical scale used to
express the acidity or basicity (alkalinity) of
an aqueous solution.
NATURE OF THE pH SCALE
The pH scale is logarithmic in nature. This means that each
whole number represents a tenfold increase or decrease in
the hydrogen ion concentration. For example, a solution with
a pH level of 3 is 10 times more acidic than one with a pH
level of 4.
The pH scale is inversely proportional to the hydrogen ion
concentration. This means that the higher the concentration,
the lower the pH value of the solution becomes and the
more acidic it is.
Because of the negative sign in the formula, as the
hydrogen ion concentration (H+) increases, the pH value
decreases. Conversely, as the hydrogen ion concentration
decreases, the pH value increases.
REASONS FOR THE
DEVELOPMENT OF THE pH SCALE
The major reason for the development of the pH
scale was because scientists at the time were using
color changes to indicate acidity or basicity, but a
more precise and numerical way was needed.
It was also created to avoid the inconvenience of
using negative indices and to accommodate a wide
range of H+ and OH- concentrations which are
commonly encountered in acid-base reactions
IMPORTANCE OF THE pH SCALE
Plant Growth:
•Soil pH: Different plants have optimal pH ranges for growth, and the availability
of nutrients in the soil is affected by pH.
•Nutrient Uptake: Soil pH affects how plants absorb essential nutrients. For
example, acidic soils can limit the availability of certain nutrients like
phosphorus, while alkaline soils can limit iron uptake.
Environmental Effects:
•Soil Health: Soil pH is an indicator of soil health, influencing
crop yields, microbial activity, and overall ecosystem function.
•Pollution: Industrial and agricultural activities can release acidic
or basic substances into the environment, affecting both soil and
water pH.
Material Performance:
•Corrosion: pH can affect the corrosion of metals. For example,
acidic environments can accelerate the rusting of iron.
•Cleaning Agents: pH plays a role in the effectiveness of
cleaning products. Some cleaning agents are acidic, while others
are basic, and their effectiveness depends on the target surface
and the pH of the solution.
And we wouldn’t be able to know all this without Sorenson and
his pH scale.
TO CONCLUDE, LET’S WATCH A SHORT
VIDEO TO SHED MORE LIGHT ON THIS
TOPIC
