When the concentration of the hydroxyl ions is equal to that of the
hydrogen ions, the concentration of hydroxyl ions is also of a
10,000,000
mole or 10~^. This is the neutral point. The term pH is used to denote the
concentration of the hydrogen ions only. Sometimes />OH is used to denote
the concentration of the hydroxyl ions. Thus when the concentration of the
hydrogen ions is pH 7, that of the hydroxyl ions is pOH 7. If the con-
centration of the hydroxyl ions is multiplied by the concentration of the
hydrogen ions a definite product is obtained. In fractions this would be
written thus :
X
10,000,000 10,000,000 100,000,000,000,000
But in the exponential notation it is expressed as follows:
10-7 X 10-7 = 10-1^
When the hydrogen-ion concentration in a solution is increased, the hy-
droxyl-ion concentration is decreased, so that the product of the concentra-
tion of the hydrogen and hydroxyl ions always gives 10~^^, and this is a
constant for the product of these two ions. Thus in a solution that has a
pH 6 the hydrogen ions exceed the hydroxyl ions but the product of their
concentrations is the constant 10^^^. In a solution that has a pH 6 the
concentration of the hydrogen ions expressed in fractions is ^^ of
1,000,000
a mole of hydrogen. In the same solution the concentration of the hy-
droxyl ions is ^ of a mole. The product of these two concentra-
^ 100,000,000
28 RELATION OF COOKERY TO COLLOID CHEMISTRY
tions gives the constant. Expressed in exponential notation it is 10"^ X
10"^ = 10"^"*. In a solution that has a pH 8 the hydroxyl ions exceed the
hydrogen ions but the product of their concentration is again 10"^^. When
the concentration of the hydrogen ions is pH 3 or 10~^ then the concentra-
tion of the hydroxyl ions is 10"^^ and their product is again 10^^^.
Literally, the term pH means to a power. It is used to express the re-
action of a fluid, that is, its degree of acidity or alkalinity, but it does not
do this directl)^, as is shown in the above equations. It is an inverse logarith-
mic function, deprived of its minus sign. Experimentally it is determined
electrometrically and is really a number obtained from determining the
electromotive force (E.M.F. ) of a substance in a suitable apparatus and
by using this value of (E.M.F.) in a formula, computing the pH.
Hydrogen-ion concentration refers to the concentration of the ionized or
active ions per liter of substance. The pH value does not represent this
directly but for all practical purposes may be taken as a value represent-
ing it.
The relation of hydrogen-ion concentration and />H values in solutions
of varying normalities is given below.
TABLE 3
Solution
Grams of hydroo;en
ion per Hter
pH value
Normal
1.0
0
N/m
0.1
1
A/ 100
0.01
2
A/ 1000
0.001
3
A/ 10, 000
0.0001
4
A/ 100, 000
0.00001
5
A/ 1,000, 000
0.000001
6
A/ 10, 000, 000
0.0000001
7
The above arrangement shows that the pH value is not an arithmetical
series or ratio but varies according to the logarithmic notation. Thus />H 2
is not one-half of pH 1 but one-tenth of it.
The number of times the hydrogen-ion and hydroxyl-ion concentrations
of a solution exceed that of pure water may be shown as follows. The
arrangement is by Alexander.
Page 27
Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
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When the concentration of the hydroxyl ions is equal to that of the
hydrogen ions, the concentration of hydroxyl ions is also of a
10,000,000
mole or 10~^. This is the neutral point. The term pH is used to denote the
concentration of the hydrogen ions only. Sometimes />OH is used to denote
the concentration of the hydroxyl ions. Thus when the concentration of the
hydrogen ions is pH 7, that of the hydroxyl ions is pOH 7. If the con-
centration of the hydroxyl ions is multiplied by the concentration of the
hydrogen ions a definite product is obtained. In fractions this would be
written thus :
X
10,000,000 10,000,000 100,000,000,000,000
But in the exponential notation it is expressed as follows:
10-7 X 10-7 = 10-1^
When the hydrogen-ion concentration in a solution is increased, the hy-
droxyl-ion concentration is decreased, so that the product of the concentra-
tion of the hydrogen and hydroxyl ions always gives 10~^^, and this is a
constant for the product of these two ions. Thus in a solution that has a
pH 6 the hydrogen ions exceed the hydroxyl ions but the product of their
concentrations is the constant 10^^^. In a solution that has a pH 6 the
concentration of the hydrogen ions expressed in fractions is ^^ of
1,000,000
a mole of hydrogen. In the same solution the concentration of the hy-
droxyl ions is ^ of a mole. The product of these two concentra-
^ 100,000,000
28 RELATION OF COOKERY TO COLLOID CHEMISTRY
tions gives the constant. Expressed in exponential notation it is 10"^ X
10"^ = 10"^"*. In a solution that has a pH 8 the hydroxyl ions exceed the
hydrogen ions but the product of their concentration is again 10"^^. When
the concentration of the hydrogen ions is pH 3 or 10~^ then the concentra-
tion of the hydroxyl ions is 10"^^ and their product is again 10^^^.
Literally, the term pH means to a power. It is used to express the re-
action of a fluid, that is, its degree of acidity or alkalinity, but it does not
do this directl)^, as is shown in the above equations. It is an inverse logarith-
mic function, deprived of its minus sign. Experimentally it is determined
electrometrically and is really a number obtained from determining the
electromotive force (E.M.F. ) of a substance in a suitable apparatus and
by using this value of (E.M.F.) in a formula, computing the pH.
Hydrogen-ion concentration refers to the concentration of the ionized or
active ions per liter of substance. The pH value does not represent this
directly but for all practical purposes may be taken as a value represent-
ing it.
The relation of hydrogen-ion concentration and />H values in solutions
of varying normalities is given below.
TABLE 3
Solution
Grams of hydroo;en
ion per Hter
pH value
Normal
1.0
0
N/m
0.1
1
A/ 100
0.01
2
A/ 1000
0.001
3
A/ 10, 000
0.0001
4
A/ 100, 000
0.00001
5
A/ 1,000, 000
0.000001
6
A/ 10, 000, 000
0.0000001
7
The above arrangement shows that the pH value is not an arithmetical
series or ratio but varies according to the logarithmic notation. Thus />H 2
is not one-half of pH 1 but one-tenth of it.
The number of times the hydrogen-ion and hydroxyl-ion concentrations
of a solution exceed that of pure water may be shown as follows. The
arrangement is by Alexander.