This document discusses various concepts related to ionic equilibrium in solution including strong and weak electrolytes, acid-base theories of Arrhenius, Bronsted-Lowry, and Lewis. It defines strong electrolytes as completely dissociating in water and weak electrolytes as achieving an equilibrium between dissociated and undissociated molecules. Acids are defined as proton donors and bases as proton acceptors under the Bronsted-Lowry theory. The Lewis theory further defines acids as electron pair acceptors and bases as electron pair donors. Dissociation constants and factors affecting acid strength are also covered.
Acid base Theories
Role of the solvents
Acid base dissociation constant,
Relative strength of acids and bases
Distribution of acid base species with pH
Buffer solution
Henderson Hasselbalch equation,
Indicators, Mixed indicators
Different type of titrations (Neutralization curves)
Polyprotic systems,
Phosphoric acid system,
Polyamine and amino acid systems.
Titration of sodium carbonate
Lavoisier definition
Liebig definition
Arrhenius Acids and Bases
Bronsted-Lowry Acid and Base
Lewis Acid and Base
Solvent-system Concept
Lux-Flood Concept
Pearson’s Concept
Historically, the first of the scientific concepts of acids and bases was provided by the French chemist Antoine Lavoisier, circa 1776.
Lavoisier's knowledge of strong acids was mainly restricted to oxyacids, which tend to contain central atoms in high oxidation states surrounded by oxygen, such as HNO3 and H2SO4, and he was not aware of the true composition of the hydrohalic acids, HCl, HBr, and HI. From his limited knowledge,
He defined acids in terms of their content of oxygen, and he named oxygen from Greek words meaning "acid-former"
Acid base Theories
Role of the solvents
Acid base dissociation constant,
Relative strength of acids and bases
Distribution of acid base species with pH
Buffer solution
Henderson Hasselbalch equation,
Indicators, Mixed indicators
Different type of titrations (Neutralization curves)
Polyprotic systems,
Phosphoric acid system,
Polyamine and amino acid systems.
Titration of sodium carbonate
Lavoisier definition
Liebig definition
Arrhenius Acids and Bases
Bronsted-Lowry Acid and Base
Lewis Acid and Base
Solvent-system Concept
Lux-Flood Concept
Pearson’s Concept
Historically, the first of the scientific concepts of acids and bases was provided by the French chemist Antoine Lavoisier, circa 1776.
Lavoisier's knowledge of strong acids was mainly restricted to oxyacids, which tend to contain central atoms in high oxidation states surrounded by oxygen, such as HNO3 and H2SO4, and he was not aware of the true composition of the hydrohalic acids, HCl, HBr, and HI. From his limited knowledge,
He defined acids in terms of their content of oxygen, and he named oxygen from Greek words meaning "acid-former"
Solvent system definition of acids and basesSourovPaul6
This PPT is about the solvent system definition of acids and bases in inorganic chemistry . This power point is useful to those who study chemistry in college and also useful for University students and also for PhD students
Acids and bases buffers ARRHENIUS CONCEPT
THE LEWIS CONCEPT-THE ELECTRON DONOR ACCEPTOR SYSTEM
BRONSTED-LOWRY CONCEPT (PROTON TRANSFER
THEORY
buffer action
ph scale
buffer capacity
acid base balance
isotonicity method
isotonic soltions
buffer solutions in pharmaceutical preparations
Solvent system definition of acids and basesSourovPaul6
This PPT is about the solvent system definition of acids and bases in inorganic chemistry . This power point is useful to those who study chemistry in college and also useful for University students and also for PhD students
Acids and bases buffers ARRHENIUS CONCEPT
THE LEWIS CONCEPT-THE ELECTRON DONOR ACCEPTOR SYSTEM
BRONSTED-LOWRY CONCEPT (PROTON TRANSFER
THEORY
buffer action
ph scale
buffer capacity
acid base balance
isotonicity method
isotonic soltions
buffer solutions in pharmaceutical preparations
• Acid-base concept
• Role of this form of titration in pharmaceutical quality assurance
• Ionization
• Low of ionization
• Henderson hasselbarkh equation equation
• Neutralization curves
• Acid-base indicators
• Mixed indicators used in polyprotic & amino acid systems during amino acid titration
University of Southern Mindanao
2 BS Pharmacy A (AY: 2023-2024)
PHARM 12 - Physical Pharmacy
All About pH and Buffers This contains the topics about Acids, Bases and Buffers.
REFERENCES
7.1A: Acid-Base Theories and Concepts. (2017, June 3). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Map%3A_Inorganic_Chemistry_(Housecroft)/07%3A_Acids_bases_and_ions_in_aqueous_solution/7.01%3A_Introduction/7.1A%3A_Acid-Base_Theories_and_Concepts#:~:text=There%20are%20three%20primary%20theories
Applied Physical Pharmacy (2014) McGraw-Hill Education. ISBN: 978-0-07-180442-4
Abdella, S., Abid, F., Youssef, S. H., Kim, S., Afinjuomo, F., Malinga, C., Song, Y., & Garg, S. (2023). pH and its applications in targeted drug delivery. Drug Discovery Today, 28(1), 103414. https://doi.org/10.1016/j.drudis.2022.103414
Admin. (2022, December 1). Ionization Of Water - Nature of Water, Detailed explanation of Self Ionization of Water and Pure water’s Ion. BYJUS. https://byjus.com/chemistry/ionization-of-water/
Byju’s. (2022, July 4). Is NaCl it An Acid or Base-. https://byjus.com/question-answer/is-nacl-an-acid-or-base/
Johnston, M. (2023, April 9). Hydrogen: What’s the difference between H, H2, H+, H- and OH- ? Watermatters.
https://www.watermatters.ca/blogs/articles/hydrogen-what-s-the-difference-between-h-h2-h-h-and-oh
Libretexts. (2023, July 18). 14.2: Ionization of Water. Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/General_Chemistry/ChemPRIME_(Moore_et_al.)/14%3A_Ionic_Equilibria_in_Aqueous_Solutions/14.02%3A_Ionization_of_Water
Niederquell, A., Stoyanov, E. V., & Kuentz, M. (2023). Physiological buffer effects in drug supersaturation - A mechanistic study of hydroxypropyl cellulose as precipitation inhibitor. Journal of Pharmaceutical Sciences, 112(7), 1897–1907. https://doi.org/10.1016/j.xphs.2023.02.013
pH of Salts in Water | Department of Chemistry | University of Washington. (n.d.). https://chem.washington.edu/lecture-demos/ph-salts-water#:~:text=Since%20this%20reaction%20produces%20OH,sodium%20acetate%20solution%20is%20basic.
Reset Help By the Brnsted-Lowry definition- acids are proton donors an.docxacarolyn
Reset Help By the Brønsted-Lowry definition, acids are proton donors and bases are proton acceptors. By the Lewis definition, acids are electron-pair acceptors and bases are electron-pair donors. For bases, the two definitions are equivalent such that all Lewis bases are Brønsted-Lowry bases and vice versa However, it is possible to have a Lewis acid that is not a Brønsted-Lowry acid. This is because Lewis acids include molecules and cations that have a vacant valence orbital, regardless of whether they have a proton to donate Common examples of Lewis acids (that are not Brønsted-Lowry acids) are metal ions, such as Al+and Cu2+. The following is an example ofa Lewis acid-base reaction Lewis acids Lewis bases NH3 donates the electron pair to Cu2+. Therefore NH3 is a Lewis base, and Cu2 is a Lewis acid SubmitPrev Previous Answer
Solution
1. Lewis acids: Lewis acids are the species which accepts electrons.
SO 3 since S has only three electron domains. Hence it accepts electrons.
Fe 2+ is electron deficient. Hence it accepts electrons too.
CO 2 where C accepts electrons since it is bound to two highly electronegative oxygen atoms.
Lewis bases are species that donates electrons.
I - , CO, H - , CH 3 NH 2
2. The order of decreasing pH is:
Ba(OH) 2 > NaOH > N 2 H 4 > HOCl > HCl
Ba(OH) 2 decomposes to give 2 OH - ions. This is why it has higher pH than NaOH which decomposes to give only 1 OH - ion.
Hydrazine N 2 H 4 is basic however lesser than NaOH and Ba(OH) 2
HOCl is a weak acid that partially dissociates to give H + and ClO -
HCl is the strongest acid that completely dissociates into H + and Cl - and hence has the lowest pH.
More the H + ions in solution, lesser the pH.
More the OH - ions in solution, higher the pH.
3. Given,
[ OH - ] = 2.3 x 10 -2 M
We know that at 25 0 C,
[H + ] [OH - ] = Kw = Ionic product of water = 10 -14
Putting the value of [OH - ] in the above equation, we have,
[H + ] x 2.3 x 10 -2 = 10 -14
[H + ] = 10 -14 / (2.3 x 10 -2 )
[H + ] = 0.44 x 10 -12 M
.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
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Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
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A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
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Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
2. 2
Electrolytes when dissolved in water splits up
into charged particles called ions.. The
process is called ionisation or dissociation.
Certain electrolytes such as NaCl, KCl, HCl
are almost completely ionised in solutions.
The electrolytes which are almost
completely ionised in their solutions are
called strong electrolytes .
3. 3
Strong electrolytes are:
1.All water soluble salts
(KCl,Na2SO4,Ca(NO3)2 ,etc.
2.Alkalines (NaOH, KOH, Ca(OH)2, Ba(OH)2),
etc.
3.Mineral acids (H2SO4, HNO3, HCl, HBr,
HI),etc.
The equation for dissociation of strong electrolytes
are written with only a single arrow directed to the
right.
KCl(aq) → K+
(aq) + Cl −
(aq)
4. 4
On the other hand, electrolytes which are
weakly ionised in their solutions are
called weak electrolytes . In case of
solutions of weak electrolytes, the ions
produced by dissociation of electrolyte
are in equilibrium with undissociated
molecules of the electrolyte.
NH4OH(aq) NH4
+
(aq) + OH−
(aq)
Equations for the dissociation of weak electrolytes
are written with double arrows( ).
CH3
COOH(aq) CH3
COO−
(aq) + H+
(aq)
5. 5
VARIOUS CONCEPTS OF ACIDS AND BASES
1.ARRHENIUS CONCEPT OF ACIDS AND BASES.
According to Arrhenius concept , an acid is
a substance which can furnish hydrogen
ions in its aqueous solution . A base is a
substance which can furnish hydroxyl
ions in its aqueous solution .
For example, substances such as HNO3
, HCl,
CH3
COOH etc are acids, whereas substances
such as NaOH , KOH , NH4
OH etc. are bases,
according to this concept.
7. . 7
According to Arrhenius theory , neutralisation
of acids and bases is basically a reaction
between H+
and OH−
ions in solutions.
H +
+ OH− H2
O
8. 8
2.BRONSTED-LOWRY CONCEPT OF ACIDS AND
BASES.
The Brønsted-Lowry definition, formulated in 1923,
independently by Johannes Nicolaus Brønsted in
Denmark and Martin Lowry in England
It is based upon the idea of protonation of bases
through the de-protonation of acids
Johannes Nicolaus Brønsted Martin Lowry
9. 9
They proposed that : An acid is a
substance that can donate a proton. A
base is a substance that can accept a
proton .
These definitions are more general
because according to these definitions
even ions can behave as acids or bases.
Moreover, these definitions are not
restricted to reactions taking place in
aqueous solutions only.
10. 10
It is a reversible reactions that involve proton
transfer from the acid to the base
HA + B HB+
+ A−
Acid Base
Acid is known as Proton Donor.
Base is known as Proton Acceptor.
HCl → H+
+ Cl−
Acid ( Proton Donor, donate H+
)
Base ( Proton Acceptor, accept H+
)
12. 12
In both Arrhenius and Bronsted concepts, acids are
sources of protons. Hence all Arrhenius acids are
also Bronsted acids. However, there is a difference in
the definition of bases. Arrhenius theory requires
base to the source of OH−
ions in aqueous medium,
but Bronsted theory requires base to be a proton
acceptor. Hence Arrhenius bases may not be
Bronsted bases. For example, NaOH is a base
according to Arrhenius theory because it gives OH−
ions in aqueous solution, but NaOH does not accept
proton as such. Hence it may not be classified as a
base according to Bronsted theory.
13. 13
Strengths of acids and bases.
Strength of an acid is measured in terms of its
tendency to lose proton whereas strength of a base
is measured in terms of its tendency to accept
proton. The conjugate base of a strong acid is a
weak base.
HCl(aq) H +
+ Cl−
(aq)
strong acid weak base
14. 14
On the other hand, conjugate base of a weak
acid is a strong base.
CH3COOH(aq) H+
(aq) + CH3
COO−
(aq)
weak acid strong base
The strength of acids or bases is
experimentally measured by determining its
ionisation or dissociation constants.
15. 15
3. THE LEWIS ACIDS AND BASES.
Although Bronsted-Lowry theory was more
general than Arrhenius theory of acids and
bases , but failed to explain the acid base
reactions which do not involve transfer of
protons. For example it fails to explain how
acidic oxides such as anhydrous CO2
, SO2
,
SO3
etc. can neutralise basic oxides such as
CaO, BaO etc. even in absence of solvent.
16. 16
Lewis proposed a more general definition
for acids and bases, which do not require
the presence of protons to explain the
acid-base behaviour.
Accoding to Lewis concept :
An acid is a substance which can accept a
pair of electrons.
A base is a substance which can donate a
pair of electrons .
17. 17
Acid-base reactions according to this concept
involve the donation of electron pair by a
base to an acid to form a co-ordinate bond.
Lewis bases can be neutral molecules such
as :
having one or more unshared pairs of
electrons. , or anions such as : −CN−
, −OH−
,
−Cl−
, etc.
18. . 18
Lewis acids are the species having
vacant orbitals in the valence shell of
one of its atoms. The following species
can act as Lewis acids.
Molecules having an atom with
incomplete octet.
20. 20
It may be noted that all Bronsted bases are
also Lewis bases but all Bronsted acids are not
Lewis acids. Lewis bases generally contain one
or more lone pairs of electrons and therefore ,
they can also accept a proton (Bronsted base).
Thus, all Lewis bases are also Bronsted bases.
On the other hand, Bronsted acids are those
which can give a proton, for example , HCl,
H2
SO4
. But they are not capable of accepting a
pair of electrons .
Hence , all Bronsted acids are not Lewis acids.
21. . 21
THE DISSOCIATION CONSTANTS OF ACIDS (Ka
)
Strong acids dissociate almost
completely in water and therefore the
molar concentrations of H+
ions in the
solution is same as that of acid itself.
But weak acids are not completely
dissociated and relative strengths of
weak acids can be compared in terms of
their dissociation constants. For
example, the dissociation equilibrium of
an acid HA may be represented as :
22. 22
HA(aq) H+
(aq) + A −
(aq)
Applying the law of Chemical equilibrium:
Here Ka
is called dissociation constant of
the acid.
23. 23
The value of dissociation constant gives an
idea about the relative strength of the acid.
Larger the value of K a ,greater is the
concentration of H+
ions and stronger is the
acid. If dissociation constants of two acids
are known, their relative strength can be
compared. For example, consider the
following examples:
CH3
COOH(aq) H+
(aq) +CH3
COO−
(aq)
24. 24
Factors affecting acid strength
The extent of dissociation of an acid depends on the
strength and polarity of the H−A bond. In general ,
when strength of H−A bond decreases , that is , the
energy required to break the bond decreases. HA
becomes a stronger acid. Also, when the H−A bond
becomes a stronger acid. Also, when the H−A bond
becomes more polar i.e., the electronegativity
difference between the atoms H and A increases and
there is marked charge separation, cleavage of bond
becomes thereby increasing the acidity. But it
should be noted that while comparing elements in
the same group of the periodic table, H−A bond
strength is a more important factor in determining
acidity than its polar nature.
25. . 25
As the size of A increases down the
group, H−A bond strength decreases
and so the acid strength increases. For
example,
26. 26
Degree of ionisation (α) = (Number of
ions (n)) ÷ (Total number of ions and
molecules (N)).
α =
27. 27
According to Arrhenius theory of electrolyte
dissociation, the molecules of an electrolyte
in solution are constantly splitting up into
ions and the ions are constantly reuniting to
form unionized molecules. Therefore, a
dynamic equilibrium exists between ions and
unionized molecules of the electrolyte in
solution. It was pointed out by Ostwald that
like chemical equilibrium, law of mass action
can be applied to such systems also.
Ostwald’s Delution Law.
28. 28
H3
CCOOH(aq) H+
(aq) + CH3
COO−
(aq)
where:
Ka: constant of dissociation
α: degree of dissociation
C(CH3COO-
): concentrations of anions
C(H+
): concentration of cations
C(CH3COOH): concentration of
associated electrolyte.
C(1-α) Cα Cα
30. . 30
Knowing the value of Ka , it is possible to calculate
the degree of ionisation of weak acid at any
particular concentration C.
Knowing the value of Ka , it is possible to calculate
the degree of ionisation of weak acid at any
particular concentration C.
Thus, degree of dissociation
of a weak electrolyte is
proportional to the square
root of dilution.
31. 31
SOLUBILITY PRODUCT CONSTANT
Certain electrolytes such as BaSO4
and AgCl are sparingly
soluble in water. Even in their saturated solutions, the
concentration of the electrolytes is very low. So , whatever
little of electrolyte goes into solution, undergoes complete
dissociation (due to low concentration). Therefore , in
saturated solutions of such electrolytes solid electrolyte is in
equilibrium with the ions as represented below :
Consider a saturated solution of a salt containing the solid
salt. There are two equilibria, one between solid salt and
dissolved salt and second between the dissolved salt and its
ions.
AB A+
+ B− AB
(solid salt) (dissolved salt) (ions)
32. 32
Applying the Law of mass action to the second
equilibrium,
where K is the equilibrium constant and [AB] is the
concentration of the dissolved salt. Cross
multiplying we get
K[AB] = [A+
] [B−
]
Since the solution is saturated , the concentration of
the dissolved salt remains constant at a fixed
temperature.
33. . 33
Hence . [A+
] [B−
]= K × Constant = KSp
where KSp
is another
constant. This constant K sp is known as the solubility
product of the electrolyte. It is the maximum value of product
of concentrations of the ions of the electrolyte.
In the case of silver chloride, we have :
AgCl Ag+
+ Cl−
KSp = [Ag+
] [Cl−
]
In general , for any sparingly soluble salt Ax By which
dissociates to set up the equilibrium :
Ax
By x Ay+
y Bx−
34. 34
where Ay+
and Bx−
denote the positive and
negative ions , x and y represent the number
of these ions in the formula of the electrolyte.
The solubility product constant may be
expressed as :
KSp = [Ay+
]x
[Bx−
]y
Thus solubility product of a sparingly soluble salt at a
given temperature may be defined as the product of
the concentrations of its ions in the saturated
solution, with each concentration term raised to the
power equal to the number of times the ion occurs
in the equation representing the dissociation of the
electrolyte.
35. 35
KSp = [A+
] [B−
] = S × S = S2
Suppose at a particular temperature its solubility is
S mol L−1
. S moles of salt on ionisation give S moles
of A+
and S moles of B−
ions.
AB A+
(aq) + B−
(aq)
In general , for any sparingly soluble salt A x B y
which dissociates to set up the equilibrium :
Ax By In general , for any sparingly
soluble salt A x B y which dissociates to set up the
equilibrium :
Ax By
x Ay+
y Bx−
[Ay+
] = x S and [Bx−
] = y S
36. 36
KSp =[x S]x
[y S ]y
= xx
yy
S(x+y)
The concept of solubility product principle helps us to predict
whether a salt will precipitate or not.
Precipitation occurs : if calculated ionic product > K sp
No precipitation : if calculated ionic product < KSp
.