This document provides an overview of acid-base theories and properties. It covers the Bronsted-Lowry and Lewis theories of acids and bases. It defines strong and weak acids and bases, and how their strength affects properties like conductivity and reaction rate. It also introduces the pH scale and explains how pH is determined by the concentration of hydrogen ions in solution.
The oral fast-dissolving film is an advanced, patient compliant and novel delivery system. The acceptance of this ingenious dosage form is increasing day by day due to its several comparative advantages of being cost-benefit, rapid dissolving without water aid, as well as greatly compliant to both geriatric and pediatric patients in emergency conditions and specific diseases. Moreover, it is a worthwhile dosage form for the drug experiencing pre-systemic metabolism and lesser bioavailability. This review article covers history, advantages, disadvantages, limitations, ideal properties, classification, formulation consideration, method of manufacturing, quality parameters both in-vitro and in-vivo, advancement in technology, commercial trends and literature review of the previous work for oral fast dissolving films. It can be concluded that it one of the fastest-growing dosage forms holding a lot of potentials especially for commercial use due to its unique characteristics, novel attributes, competitive standing, and cost-adequacy
Oral Films Development & Manufacturing in India - Current ScenarioSridhar Rudravarapu
This presentation depicts the current status of oral film development and manufacturing in India. Oral film (orodispersible & oromucosal film) is a novel and alternate dosage delivery system with a huge scope for application in the pharma and nutraceuticals industry. This presentation orients the customers at the level of patients, health professionals and manufacturing companies about the oral films product development process, manufacturing aspects, and regulatory steps involved in the approval of these by the drug control authority in India. This presentation aims to briefly cover all the aspects of oral films (orodispersible/oromucosal) development and manufacturing feasibility in India to maximize its application for multiple health and patient compliance benefits -- Sridhar Rudravarapu
The oral fast-dissolving film is an advanced, patient compliant and novel delivery system. The acceptance of this ingenious dosage form is increasing day by day due to its several comparative advantages of being cost-benefit, rapid dissolving without water aid, as well as greatly compliant to both geriatric and pediatric patients in emergency conditions and specific diseases. Moreover, it is a worthwhile dosage form for the drug experiencing pre-systemic metabolism and lesser bioavailability. This review article covers history, advantages, disadvantages, limitations, ideal properties, classification, formulation consideration, method of manufacturing, quality parameters both in-vitro and in-vivo, advancement in technology, commercial trends and literature review of the previous work for oral fast dissolving films. It can be concluded that it one of the fastest-growing dosage forms holding a lot of potentials especially for commercial use due to its unique characteristics, novel attributes, competitive standing, and cost-adequacy
Oral Films Development & Manufacturing in India - Current ScenarioSridhar Rudravarapu
This presentation depicts the current status of oral film development and manufacturing in India. Oral film (orodispersible & oromucosal film) is a novel and alternate dosage delivery system with a huge scope for application in the pharma and nutraceuticals industry. This presentation orients the customers at the level of patients, health professionals and manufacturing companies about the oral films product development process, manufacturing aspects, and regulatory steps involved in the approval of these by the drug control authority in India. This presentation aims to briefly cover all the aspects of oral films (orodispersible/oromucosal) development and manufacturing feasibility in India to maximize its application for multiple health and patient compliance benefits -- Sridhar Rudravarapu
Content:
Introduction
Ideal Properties
Advantages
Limitations
Types of Microsphere
Method for Preparation
Polymer Used for Preparation
Release of Drug from Microsphere
Application
Formulation and Evaluation of Nimodipine Tablet by Liquisolid Techniqueijtsrd
Liquisolid technique is novel concept of the drug delivery via the oral route. This technique is applied to poorly water soluble , water insoluble or lipophilic drugs. According to the new formulation method of liquisolid compact, liquid medication such as solution or suspensions of water insoluble drug in suitable non volatile solvent can be converted into acceptably flowing and compressible powders by blending with selected powder excipients. The present work endeavour is directed towards the development of liquisolid compact for production of immediate release tablet of water insoluble Nimodipine. Liquisolid compacts were prepared by using polyethylene glycol 300 as the liquid vehicle or non volatile solvent. Crospovidone was used as a superdisintegrating agent and PVP K30 as a binder. Microcrystalline cellulose was used as a absorbing carrier and silicone dioxide as adsorbing coating material. The prepared liquisolid system were evaluated for their micromeretic properties and possible drug excipients interaction . The FTIR spectra study ruled out any interaction between the drug and excipients in preparation of Nimodipine liquisolid compact. The in vitro dissolution study confirmed enhance drug release from liquisolid compacts by using USP type I basket in 0.5 SLS in water. The selected optimal formula released 93.86 of its content in 30 min which is showing immediate release. The results showed that use of superdisintegrants had remarkable impact on the release rate of Nimodipine from Liquisolid compact, enhancing the release rate of the drug from liquisolid compact. Neha Durge | Kirti Parida ""Formulation and Evaluation of Nimodipine Tablet by Liquisolid Technique"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-4 , June 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23863.pdf
Paper URL: https://www.ijtsrd.com/pharmacy/pharmaceutics/23863/formulation-and-evaluation-of-nimodipine-tablet-by-liquisolid-technique/neha-durge
GASTRO RETENTIVE DRUG DELIVERY SYSTEM, GRDDS, DRUG DELIVERY SYSTEM IN STOMACH...CHANDIGARH UNIVERSITY
Gastro-retentive drug delivery is an approach to prolong gastric residence time, thereby targeting site-specific drugs released in the upper gastrointestinal tract (GIT) for local or systemic effects. It is obtained by retaining dosage form in the stomach and by releasing them in a controlled manner. In this presentation, I have explained GRDDS and the different types of GRDDS. How drug works in stomach.
Content:
Introduction
Ideal Properties
Advantages
Limitations
Types of Microsphere
Method for Preparation
Polymer Used for Preparation
Release of Drug from Microsphere
Application
Formulation and Evaluation of Nimodipine Tablet by Liquisolid Techniqueijtsrd
Liquisolid technique is novel concept of the drug delivery via the oral route. This technique is applied to poorly water soluble , water insoluble or lipophilic drugs. According to the new formulation method of liquisolid compact, liquid medication such as solution or suspensions of water insoluble drug in suitable non volatile solvent can be converted into acceptably flowing and compressible powders by blending with selected powder excipients. The present work endeavour is directed towards the development of liquisolid compact for production of immediate release tablet of water insoluble Nimodipine. Liquisolid compacts were prepared by using polyethylene glycol 300 as the liquid vehicle or non volatile solvent. Crospovidone was used as a superdisintegrating agent and PVP K30 as a binder. Microcrystalline cellulose was used as a absorbing carrier and silicone dioxide as adsorbing coating material. The prepared liquisolid system were evaluated for their micromeretic properties and possible drug excipients interaction . The FTIR spectra study ruled out any interaction between the drug and excipients in preparation of Nimodipine liquisolid compact. The in vitro dissolution study confirmed enhance drug release from liquisolid compacts by using USP type I basket in 0.5 SLS in water. The selected optimal formula released 93.86 of its content in 30 min which is showing immediate release. The results showed that use of superdisintegrants had remarkable impact on the release rate of Nimodipine from Liquisolid compact, enhancing the release rate of the drug from liquisolid compact. Neha Durge | Kirti Parida ""Formulation and Evaluation of Nimodipine Tablet by Liquisolid Technique"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-4 , June 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23863.pdf
Paper URL: https://www.ijtsrd.com/pharmacy/pharmaceutics/23863/formulation-and-evaluation-of-nimodipine-tablet-by-liquisolid-technique/neha-durge
GASTRO RETENTIVE DRUG DELIVERY SYSTEM, GRDDS, DRUG DELIVERY SYSTEM IN STOMACH...CHANDIGARH UNIVERSITY
Gastro-retentive drug delivery is an approach to prolong gastric residence time, thereby targeting site-specific drugs released in the upper gastrointestinal tract (GIT) for local or systemic effects. It is obtained by retaining dosage form in the stomach and by releasing them in a controlled manner. In this presentation, I have explained GRDDS and the different types of GRDDS. How drug works in stomach.
pH is a measure of the acidity or basicity of a solution. It is defined as the cologarithm of the activity of dissolved hydrogen ions (H+). Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations. The pH scale is not an absolute scale; it is relative to a set of standard solutions whose pH is established by international agreement.
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
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
2. Lesson 1: Theories of Acids/Bases
Main
Objectives:
Reflect on prior knowledge of acids and bases
Understand the Bronsted-Lowry theory of acidity and
identify Bronsted-Lowry acids and bases
Understand the Lewis theory of acidity and identify Lewis
acids and bases
3. Solubility of Acids and Akalis
Most acids are soluble or react strongly with water
Some bases are soluble, some are insoluble
Soluble bases are called ALKALIS
Main
4. Bronsted-Lowry Acids and Bases
+(aq) + OH-(aq)
Main
It’s all about protons (H+)
Acid: Proton donor
HCl(aq) H+(aq) + Cl-(aq)
H2SO4(aq) 2H+(aq) + SO4
2-(aq)
Base: Proton acceptor
NH3(aq) + H2O(l) NH4
OH-(aq)* + H+(aq) H2O(l)
*From any soluble hydroxide or other alkali
If we mention acid/base without mentioning the type, we
generally mean a Bronsted-Lowry one.
5. Conjugate Acids and Bases
A conjugate acid/base pair are two species that differ by
a single proton.
A conjugate base is a species that has one less proton
A conjugate acid is a species that has one more proton
+ is its conjugate acid
Main
For example:
Hydrochloric acid, HCl
HCl is the acid, Cl- is its conjugate base
The HCl can donate a proton…it is an acid
The Cl- could accept a proton….it is a base
Ammonia, NH3
NH3 is the base, NH4
The NH3 can accept a proton….it is a base
The NH4
+ could donate a proton….it is an acid What is the link?
6. Lewis Acids and Bases
Acid: electron pair acceptor
Species with an incomplete octet/outer-shell
Base: electron pair donor
Main
Species with a lone pair
For example:
Gilbert Lewis
7. Main
Key Points
Bronsted-Lowry Theory
Acid is a proton donor
Base is a proton acceptor
Lewis Theory
Acid is electron pair acceptor
Base is electron pair donor
9. Lesson 2: Properties of Acids and Bases
Main
Objectives:
Understand the effect of acids/alkalis on indicators
Understand that acids neutralises bases (and vice versa)
Understand the reactions of acids with:
Metals
Carbonates
Hydrogen carbonates
Conduct experiments to confirm the above properties
10. Main
Indicators
Universal (actually a mixture of indicators):
Litmus:
Acid is Red / Base is Blue
Phenolpthalein:
Acid is Colourless / Alkali is Pink
This is sorcery due to some clever chemistry that we will meet in the
HL part of the course.
11. Main
Neutralisation
ACID + ALKALI SALT + WATER
hydrochloric acid + sodium hydroxide sodium
chloride + water
sulfuric acid + ammonia ammonium sulfate + water
This is always an exothermic reaction.
It is called neutralisation but won’t always
lead to a perfectly neutral solution
12. Main
Acids and Metals
ACID + METAL SALT + HYDROGEN
phosphoric acid + magnesium magnesium
phosphate + hydrogen
ethanoic acid + sodium sodium ethanoate +
hydrogen
Very reactive metals may do this
explosively
13. Acids and Carbonates
ACID + CARBONATE SALT + CARBON DIOXIDE + WATER
hydrochloric acid + calcium carbonate calcium chloride + carbon
dioxide + water
nitric acid + sodium carbonate sodium nitrate + carbon dioxide +
water
Main
14. Acids and Hydrogencarbonates
ACID + HYDROGENCARBONATE SALT + CARBON DIOXIDE + WATER
hydrochloric acid + calcium hydrogencarbonate calcium chloride + carbon dioxide +
water
nitric acid + sodium hydrogencarbonate sodium nitrate + carbon dioxide +
water
Main
15. Main
Key Points
Acids react in similar ways to each other
Bases react in similar ways to each other
Reactions tend to neutralise acid/base properties
17. Lesson 3: The pH Scale
Main
Objectives:
Understand how pH relates to acidity/bascicity
Understand how pH relates to changes in hydrogen ion
concentration
Make a pH colour chart by diluting acids/alkalis
18. Main
The pH Scale
Runs from 1 for most acid up to 14 for most alkali?
Nonsense, can go below 0 for very strong acids and
above 14 for very strong alkalis.
19. What is pH?.....the ‘Power of Hydrogen’
pH is determined by the concentration of H+ in a solution.
Main
HL only: pH = -log10[H+]
Each one step increase in pH corresponds to a 10 fold decrease in
the concentration of H+
pH 0 : [H+] = 1.0x100 mol dm-3 (i.e. 1.0)
pH 1 : [H+] = 1.0x10-1 mol dm-3 (i.e. 0.1)
pH 2 : [H+] = 1.0x10-2 mol dm-3 (i.e. 0.01)
Follow this pattern to work out the H+ concentration required for:
pH 3
pH 5
pH 7
pH 9
pH 14
20. So a really really weak solution of an acid is
actually an alkali?
THIS IS ONLY NEEDED AT HL…MORE DETAIL LATER
No!.... Pure water exists in an equilibrium as follows:
H2O H+ + OH-
The position of the equilibrium is way over to the left.
However there is always a certain concentration of H+, even in pure
Main
water.
In pure water: [H+] = 1.00x10-7 mol dm-3
You can only get a lower concentration than this by shifting the
equilibrium to the left by adding OH-
21. Main
Key Points
pH is determined by the concentration of H+ ions
Every one step increase in pH corresponds to a ten-fold
decrease in H+ concentration
23. Lesson 4: Strong and Weak Acids and Bases
Main
Objectives:
Understand the difference between strong and weak
acids and bases
Complete an experiment to explore the difference in
properties of strong/weak acids and bases
24. Strong and Weak Acids
Main
Strong Acids:
HA(aq) H+(aq) + A-(aq) …..the acid fully dissociates into ions
For example: HCl(aq) H+(aq) + Cl-(aq)
Includes: hydrochloric, sulfuric, phosphoric, nitric
Strong acids have weak conjugate bases
Weak Acids:
HA(aq) H+(aq) + A-(aq) …..the acid only partially dissociates into ions
For example: HF(aq) H+(aq) + F-(aq)
Includes: hydrofluoric, ethanoic, carbonic
Weak acids have strong conjugate bases
25. Strong and Weak Bases
Main
Strong Bases:
BOH(aq) B+(aq) + OH-(aq) …..the base fully dissociates into ions
For example: NaOH(aq) Na+(aq) + OH-(aq)
Includes: group (I) hydroxides, barium hydroxide
Strong bases have weak conjugate acids
Weak Bases:
BOH(aq) B+(aq) + OH-(aq) …..the base only partially dissociates into ions
For example: NH3(aq) + H2O(l) NH4
+(aq) + OH-(aq)
Includes: ammonia, amines
Weak bases have strong conjugate acids
26. Main
So what?
The equilibrium has a profound effect on the
properties of the acid/base
Compared with strong acids of the same
concentration, weak acids:
Have lower electrical conductivity
React more slowly
pH is higher (less acid)
Change pH more slowly when diluted
However, they neutralise the same volume of alkali
Weak bases follow a similar pattern
27. Main
Key Points
Strong acids/bases dissociate fully into ions
Weak acids/bases only partially dissociate, forming
an equilibrium
The strong/weak character has a significant effect on
the chemical properties
28. Main
Menu
Lesson 5
HL Only
pH, pOH and the Ionic Product of Water
29. Lesson 5: pH, pOH and the Ionic Product of Water
Main
Objectives:
Understand the ionic product of water and use it calculate
H+ and OH- concentrations
Calculate pH
Calculate pOH
30. The ionic product of water, Kw
Water can be both an acid and a base, this leads to
the following equilibrium:
2 H2O H3O+ + OH- ……or more simply:
H2O H+ + OH-
The equilibrium for this reaction is called the ionic
product of water and has the symbol Kw:
[ ][ ] 1 10 14 K H OH W
Main
31. Calculating [H+] and [OH-] of pure water:
Kw = [H+][OH-] = 1.00x10-14 mol2 dm-6
Since when pure, [H+] = [OH-]
Main
[H+]2 = 1.00x10-14
[H+] = √1.00x10-14 = 1.00x10-7 mol dm-3
Kw varies with temperature:
At 273 K, Kw = 1.14x10-15, calculate [H+]
At 373 K, Kw = 5.13x10-13, calculate [OH-]
Do these changes mean the self-dissociation of water is
endothermic or exothermic? Justify your answer.
32. Calculating [H+] and [OH-] of strong acids
Main
Must use the equilibrium
For example, what is the concentration of OH- in 2.00 mol
dm-3 sulphuric acid solution?
Calculate H+ from the data given in the question, there is a
small effect from the equilibrium but it can be ignored.
Since H2SO4 produces two protons:
[H+] = 2 x 2.00 = 4.00 mol dm-3
Now we use the ionic product of water:
[H+][OH-] = 1.00x10-14
[OH-] = 1.00x10-14 / [H+] = 1.00x10-14 / 4.00
= 2.50x10-15 mol dm-3
33. Calculating [H+] and [OH-] of strong bases
Main
Must use the equilibrium
For example, what is the concentration of H+ in
0.150 mol dm-3 sodium hydroxide acid solution?
Calculate OH- from the data given in the question, there is a
small effect from the equilibrium but it can be ignored.
Since NaOH only produces one hydroxide:
[OH-] = 0.150 mol dm-3
Now we use the ionic product of water:
[H+][OH-] = 1.00x10-14
[H+] = 1.00x10-14 / [OH-] = 1.00x10-14 / 0.150
= 6.67x10-14 mol dm-3
34. Main
pH and pOH
You are familiar with the pH scale, based on [H+]:
0 (very strong acid) 7 (neutral) 14 (very strong
alkali)
There is an analogue called pOH based on [OH-]:
0 (very strong alkali) 7 (neutral) 14 (very strong
acid)
35. Calculating pH and pOH of strong acids
pH = -log10[H+] AND pOH = -log10[OH-]
For example, what is the concentration of pH and pOH of 2.00 mol dm-3
Main
sulphuric acid solution?
pH = -log10[H+] = -log10(4.00) = -0.602
pOH = -log10[OH-] = -log10(2.5x10-15)= 14.6
Note: pH + pOH = 14*…..this allows us to take a short cut:
pOH = 14 – pH = 14 – (-0.602) = 14.6
pH = 14 – pOH = 14 – 14.6 = -0.602
*This ‘14’ is known as
pKw, i.e. –log10(1.00x10-
14)
36. Calculating pH and pOH of strong bases
pH = -log10[H+] AND pOH = -log10[OH-]
For example, what is the concentration of pH and pOH of 0.150 mol dm-3
Main
sodium hydroxide acid solution?
pH = -log10[H+] = -log10(6.67x10-14) = 13.2
pOH = -log10[OH-] = -log10(0.150)= 0.824
Note: pH + pOH = 14*…..this allows us to take a short cut:
pOH = 14 – pH = 14 – (13.2) = 0.824
pH = 14 – pOH = 14 – 0.824 = 13.2
*This ‘14’ is known as
pKw, i.e. –log10(1.00x10-
14)
37. Calculating [H+] and [OH-]
Main
Very simple:
[H+] = 10-pH
For example; solution of pH 6.2
[H+] = 10-6.2 = 6.3x10-7 mol dm-3
[OH-] = 10-pOH
For example; solution of pH 6.2
pOH = 14 - 6.2 = 7.8
[OH-] = 10-7.8 = 1.6x10-8 mol dm-3
40. Lesson 6: Ka/pKa and Kb/pKb
Main
Objectives:
Understand the concepts of Ka and Kb
Understand the concepts of pKa and pKb
41. Weak Acids: Ka and pKa
Weak acids dissociate to form an equilibrium
H A
[ ][ ]
HA
[ ]
Main
HA(aq) H+(aq) + A-(aq)
This has the equilibrium constant (aka acid dissociation
constant), Ka
Ka
The values for Ka are often very small, so we use ‘pKa’ to
make them easier to handle:
pKa = -log10(Ka)
42. Acid Ka pKa
Hydronium ion, H3O+ 1.00 0.00
Oxalic acid, HO2CCO2H 5.9x10-2 1.23
Hydrofluoric, HF 7.2x10-4 3.14
Methanoic, CHOOH 1.77x10-4 3.75
Ethanoic, CH3COOH 1.76x10-5 4.75
Phenol, C6H5OH 1.6x10-10 9.80
Main
Ka and pKa in action
In order of decreasing acid strength:
Smaller Ka
weaker acid
Smaller pKa
stronger acid
43. Weak Bases: Kb and pKb
Weak bases dissociate to form an equilibrium
BOH(aq) B+(aq) + OH-(aq)
This has the equilibrium constant (aka base dissociation
B OH
[ ][ ]
BOH
[ ]
Main
constant), Kb
Kb
The values for Kb are often very small, so we use ‘pKb’ to
make them easier to handle:
pKb = -log10(Kb)
44. Base Kb pKb
Diethylamine 1.3x10-3 2.89
Ethylamine 5.6x10-4 3.25
Methylamine 4.4x10-4 3.36
Ammonia 1.8x10-5 4.74
Main
Kb and pKb in action
In order of decreasing base strength:
Smaller Kb
weaker base
Smaller pKb
stronger base
45. Measuring Ka/pKa and Kb/pKb
pKa and pKb can be determined experimentally
At the point of half neutralisation:
Main
pH = pKa
pOH = pKb
This is a convenient artefact of the mathematics
Follow the instructions here
46. Main
Key Points
For a weak acid:
H A
[ ][ ]
Ka
AND pKa = -log10(Ka)
HA
[ ]
For a weak base:
B OH
[ ][ ]
Kb
AND pKb = -log10(Kb)
BOH
[ ]
At the point of half-neutralisation:
pKa = pH AND pKb = pOH
50. We need to be able to solve problems such
as:
What is the pH of an 1.50 M solution of weak acid,
X?
What is the [OH-] of a solution of weak base, Y?
50 cm3 of a 0.1 M solution of acid X reacts with 25
cm3 of a 0.1 M solution of base Y, what is the
resulting pH?
The pH of a 0.250 M solution of weak acid Z is 5.4,
what is it’s Ka and pKa?
Main
51. We will need to use a variety of equations:
Kb
Main
New(ish) today:
Ka × Kb = Kw = 1.00x10-14
pKa + pKb = pKw = 14.0
pH + pOH = pKw = 14.0
And from previous lessons:
B OH
[ ][ ]
BOH
[ ]
H A
[ ][ ]
HA
[ ]
Ka
pKa = -log10(Ka) pKb = -log10(Kb)
pH = -log10[H+] pOH = -log10[OH-]
52. Example 1: Calculation of [OH-]
What is the concentration of OH- ions in a 0.500 mol dm-3 solution of
ammonia (Kb = 1.8x10-5)? What % of the NH3 molecules have
dissociated?
Since it is a weak base and the equilibrium is to the right we assume
that at equilibrium, [NH3] is the same as stated in the question. So:
Main
Kb = [NH4
+][OH-]/[NH3] Sub all known values into
equation
1.8x10-5 = [NH4
+][OH-]/ 0.500 Looks like there are 2 unknowns
However, since [NH4+] = [OH-]:
1.8x10-5 = [OH-]2 / 0.500 Rearrange to make [OH-] the
subject
[OH-] = √(1.8x10-5 x 0.500) Perform calculation
[OH-] = 0.0030 mol dm-3
% Dissociation = 0.0030 / 0.500 x 100 = 0.60%
53. Example 2: Calculating pH
What is the pH of a 0.225 mol dm-3 solution of oxalic acid (HOOCCOOH, Ka
= 5.9x10-2), and how does the pH change on ten-fold dilution?
Again, assume [HA] is as stated in the question
Ka = [H+][A-] / [HA] Sub in all known values
5.9x10-2 = [H+][A-] / 0.225 Looks like two unknowns, but isn’t really
This time, since oxalic acid produces two protons, [A-] = ½ [H+] so the
Main
expression becomes:
5.9x10-2 = ½ [H+]2 / 0.225 Rearrange to
make [H+] subject
[H+] = √((5.9x10-2 x 0.225) / 2) = 0.0815 mol dm-3
pH = -log10[H+] = -log10(0.0815) = 1.09
Now with the ten-fold dilution
[H+] = √((5.9x10-2 x 0.0225) / 2) = 0.0257 mol dm-3
pH = -log10[H+] = -log10(0.0257) = 1.59….i.e. ten-fold dilution increased pH by 0.50
54. Example 3: Calculating Kb from pH
A 0.0350 mol dm-3 solution of methylamine (CH3NH2) has a pH of
11.59. Determine Kb of methylamine and Ka of the methylammonium
ion (CH3NH3
Main
+).
Since pH = 11.59
pOH = 14 – 11.59 = 2.41
[OH-] = 10-2.41 = 3.92x10-3 mol dm-3
Remember:
To calculate Ka of the conjugate acid
use:
Ka x Kb = Kw
Ka = Kw / Kb
= 1.00x10-14 / 4.39x10-4
= 2.78x10-11
[BOH] at equilibrium is same as stated in question
[OH-] = [B+]
Kb = [B+][OH-]/[BOH] Known values subbed in
Kb = (3.92x10-3).(3.92x10-3)/0.0350
Kb = 4.39x10-4
55. Example 4: Calculating Ka, pKa, Kb and pKb
from each other
The pKa of benzoic acid is 4.20. Calculate Ka, Kb and
pKb
Ka = 10-pKa = 10-4.20 = 6.31x10-5
Kb x Ka = Kw
Kb = Kw / Ka = 1.00x10-14 / 6.31x10-5 = 1.58x10-10
pKb = -log10(Kb) = -log10(1.58x10-10) = 9.80
Main
OR
Since pKa + pKb = pKw
pKb = 14 – pKa = 14 – 4.20 = 9.80
56. Main
Key Points
Calculations rely on two key assumptions:
Concentration of HA or BOH at equlibrium is the same as
given in the question
Reasonable as equilibrium effects mean dissociation is often
1% or less
[H+]/[OH-] and [A-]/[B+] are not separate variables but are
related to each other
Expressing [A-]/[B+] in terms of [H+]/OH-] is a key step
58. Main
Lesson 8: Buffers
Objectives:
Describe and explain the function of buffers
Calculate the pH of buffer solutions
Make an acid and an alkaline buffer solution and observe
its buffering activity.
59. Main
Buffers
Buffers are solutions that resist changes to
their pH
Acid buffers:
Weak acid and salt of it’s conjugate base
E.g. Ethanoic acid and sodium ethanoate
Alkaline buffer:
Weak base and a salt of its conjugate acid
E.g. ammonia and ammonium chloride
Common in nature, blood being the best
example: pH kept at 7.35-7.45
60. How they work: acidic buffers
Buffer is a mixture of HA and A- solutions, establishing the following
Main
equilibrium:
HA H+ + A-
The addition of extra A- ions forces the equilibrium to the left due to
Le Chatelier’s principle. This creates a large reservoir of un-dissociated
HA
Adding acid:
Equilibrium shifts to the left, reducing the increase in H+
Adding base:
Equilibrium shifts to the right, reversing the decrease in H+
Adding water:
Both sides affected equally so pH unchanged
61. How they work: basic buffers
Buffer is a mixture of BOH and B+ solutions, establishing the
Main
following equilibrium:
BOH B+ + OH-
The addition of extra B+ ions forces the equilibrium the left due to Le
Chatelier’s principle. This creates a large reservoir of un-dissociated
BOH
Adding base:
Equilibrium shifts to the left, reducing the increase in OH-
Adding acid:
Equilibrium shifts to the right, reversing the decrease in OH-
Adding water:
Both sides affected equally so pH unchanged
62. Calculating pH of a Buffer
What is the pH of a buffer comprising a 0.450 mol dm-3 ammonia
(NH3, Kb = 1.8x10-5) and 0.200 mol dm-3 ammonium chloride?
NH OH
[ ][ ]
NH
[ ]
NH
[ ]
K
We need to make two assumptions:
Main
[NH4
4
+] is equal to that stated in the question…since there will be very little
coming from dissociated NH3
[NH3] is equal to that stated in the question…since very little NH3 has
dissociated
[ ]
log
3
10
3
4
NH
pOH pK
b
b
4.39
5
14.0 4.39 9.61
0.200
0.450
log (1.8 10 ) log10
10
pOH
pOH
pH
63. Calculating the proportions for a buffer
What mass of sodium ethanoate (Mr = 82.0) should be added to 0.500 dm3
of 0.400 mol dm-3 ethanoic acid solution (pKa = 4.76) to make a buffer of ph
5.70?
H CH COO
[ ][ ]
3
CH COOH
[ ]
H CH COO
[ ][ ]
CH COOH
[ ]
K CH COOH
[ ]
H
[ ]
a
10
0.400
K
a
CH COO
CH COO mol dm
5.7
3
10
Main
Similar to before:
Two assumptions:
3
Ka
CH3COO- will be only due to added sodium ethanoate
[CH3COOH] is as stated in the question
Note: Ka= 10-pKa
4.76
[ ]
3
[ ]
3
3
3
Mass sodium ethanoate required:
3
3.48
Mass = moles x molar mass = (3.48 x 0.500) x 82.0 = 143 g
64. Main
Key Points
Calculations are similar to those for weak acids/bases but
need re-expressing as:
B
10 BOH
B OH
[ ][ ]
BOH
[ ]
K
b
pOH pK
[ ]
[ ]
log
b
H A
[ ][ ]
HA
[ ]
K
Calculations make two key assumptions:
A
[ ]
Concentration of the weak acid/base is as stated in the
question
Concentration of the conjugate base/acid is as stated in the
question
These assumptions are valid as equilibrium effects mean very
little of the weak acid/base dissociates
[ ]
log
10 HA
pH pK
a
a
66. Lesson 9: Salt Hydrolysis
Main
Objectives:
Understand why some salts do not form neutral solutions
Predict whether a given salt will form an acidic, neutral or
alkaline solution
Complete an experiment to determine any trends in
acidity/basicity of salt solutions
67. Acid Salt Hydrolysis
When you dissolve sodium chloride in water it forms
a neutral solution of Na+ and Cl- ions:
NaCl(s) Na+(aq) + Cl-(aq)
When you dissolve ammonium chloride in water it
forms a weakly acidic solution of NH4
Main
+ and Cl- ions
Why?....discuss
68. + NH3 + H+
Main
Why acidic?
Ammonium chloride contains the NH4
+ ion
NH4
+ is the conjugate acid of the weak base NH3:
+ + OH-
NH3 + H2O NH4
The NH4
+ ion therefore is weakly acidic and will establish
the following equilibrium:
NH4
Thus, ammonium chloride will form a weakly acidic
solution
69. Basic Salt Hydrolysis
When you dissolve sodium chloride in water it forms
a neutral solution of Na+ and Cl- ions:
NaCl Na+(aq) + Cl-(aq)
When you dissolve sodium ethanoate in water it
forms a weakly basic solution of Na+ and CH3COO-ions
Main
Why?....discuss
70. Recap: Conjugate Acids and Bases
A conjugate acid/base pair are two species that differ by
a single proton.
A conjugate base is a species with has one less proton
A conjugate acid is a species with one more proton
+ is its conjugate acid
Main
For example:
Hydrochloric acid, HCl
HCl is the acid, Cl- is a conjugate base
The HCl can donate a proton…it is an acid
The Cl- could accept a proton….it is a base
Ammonia, NH3
NH3 is the base, NH4
The NH3 can accept a proton….it is a base
The NH4
+ could donate a proton….it is an acid
71. Main
Why basic?
Sodium ethanoate contains the CH3COO- ion
CH3COO- is the conjugate base of the weak acid
CH3COOH:
CH3COOH H+ + CH3COO-
The CH3COO- ion therefore is weakly basic and will
establish the following equilibrium:
CH3COO- + H2O CH3COOH + OH-
Thus, sodium ethanoate will form a weakly basic solution
72. Main
Rules of Thumb
Conjugate bases:
Conjugate bases of weak acids will form basic solutions
Conjugate bases of strong acids will form neutral
solutions
Conjugate acids:
Conjugate acids of weak bases will form acidic solutions
Conjugate acids of strong bases will form neutral
solutions
The final pH of an individual salt will depend on the
relative acidity of both the conjugate acid and
conjugate base is formed from
73. Main
Key Points
Salts of a weak acid and strong base form basic solutions:
Due to the conjugate base of the weak acid being basic
Salts of a weak base and a strong acid form acidic solutions:
Due to the conjugate acid of the weak base being acidic
Salts of a strong acid and strong base form neutral solutions
Neither the conjugate base of the acid or the conjugate acid of the
base form acid/base equilibria
Salts of a weak acid and weak base can be acidic, basic or
neutral
Depends on the relative basicity of the conjugate base and acidity
of the conjugate acid
75. Lesson 10: Acid-Base Titrations
Main
Objectives:
Complete titrations of each of the four possible
combinations of acid and base, recording data with a
data-logger
Use software to produce a graph of the results of your
titrations
Explain in full the characteristic shape of each graph
76. Anatomy of an acid-base titration curve:
In this case weak-acid/strong-base
Half-equivalence
Main
point:
i.e. Half the
volume added at
the equivalence
point
The pH of this
point is equal to
the pKa of the
weak acid.
Equivalence
point:
i.e. The point of
inflection (where
the gradient starts
to drop again).
Represents the
point at which the
acid has just been
neutralised.
pH Intercept:
Higher pH if a
weaker acid used
Buffer Region:
A lot of base has
to be added to
result in only a
small change of
pH
77. Adding acid to base
Main
Your graphs for
adding base to
acid will have
the same shape
but be mirror
images.
78. Main
Key Points
Acid-base titration curves have a characteristic
shape
The shape depends on the combination of
strong/weak acid-strong/weak base used
The pH changes very fast at the point of equivalence
due to the logarithmic nature of the pH scale
The ‘flatter’ parts of the weak acid/base curves are
due to equilibrium effects
80. Lesson 11: Indicators
Main
Objectives:
Understand how indicators work
Determine suitable indicators for a reaction
Make indicators from a range of natural products
81. Main
Indicators
An indicator is a compound whose colour depends on pH
For example:
Phenolphthalein
pH< 8: COLOURLESS pH>10: PINK
Methyl orange
pH<3.2: RED pH>4.4: ORANGE
Bromothymol blue:
pH<6.0: YELLOW pH>7.6: BLUE
Most indicators change colour only once (sometimes twice). The obvious
exception is universal indicator which is actually a mixture of several
indicators with different colour change ranges.
Note: the pH generally changes over a small range, but the logarithmic
nature of pH means often equates to a single drop.
82. How Indicators Work (what you need):
Indicators are weak acids/bases in their own right
In solution indicators form an equilibrium:
In + H+ ⇌ InH+
COULOUR 1 COLOUR 2
Main
Where: ‘In’ stands for indicator
As [H+] changes, the equilibrium moves to the left or right, thus changing the
colour
The structure of indicators change depending on the pH:
Higher pH can cause weak-acid groups to deprotonate
Low pH can cause weak-base groups to protonate
This can have knock-on effects on the structure, of the indicator molecule which
changes its colour
83. How Indicators Work (in detail):
Colour in many organic compounds comes from having overlapping π-
systems, with many delocalised electrons
+ 2H+
colourless pink
Main
For example: phenolphthalein
The colour derives from conjugated π-systems which are radically altered by
the changes in structure
The double bond on the central carbon atom allows the π-systems in the three
benzene rings to interact with each other, leading to the pink colour
This is more detail than required by the IB!!!
84. Main
pH range and pKa
Most indicators change range within ±1.0 of their pKa
pKa data for indicators can be found in your data
booklet
Indicator pKa
pH
Range
Colour Change
Acid Alkali
methyl orange 3.46 3.2–4.4 Red Yellow
bromophenol blue 4.10 3.0–4.6 Yellow Blue
bromocresol green 4.90 3.8–5.4 Yellow Blue
methyl red 5.00 4.8–6.0 Red Yellow
bromothymol blue 7.30 6.0–7.6 Yellow Blue
phenol red 8.00 6.6–8.0 Yellow Red
phenolphthalein 9.50 8.2–
10.0
Colourless Pink
85. Main
Using Indicators
Indicators are NOT USED to measure pH
Colour change is not an accurate measurement
Range of colour change limits the measurements that
could be taken
pH probes are very accurate
Indicators ARE USED:
To determine the end-point of reactions in titrations
To give a ‘rough and ready’ idea of pH
86. Main
Key Points
Indicators change colour over a narrow pH range
The colour change generally occurs at a pH within ±
1.0 of the indicator’s pKa
Indicators should be chosen with a pH range that
matches the expected equivalence point as closely
as possible
