This document provides an overview of electrochemistry concepts including resistance, conductance, conductivity, cell constant, molar conductivity, and their relationships. It discusses how these properties are affected by factors like electrolyte type, concentration, and temperature. Numerical problems demonstrate calculations of conductance, conductivity, and molar conductivity. The variation of molar conductivity with concentration is explained by the Debye-Huckel-Onsager equation and Kohlrausch's law of independent migration of ions. Limiting molar conductivity and its applications are also summarized.
This document discusses different types of diagrams used to represent the reactivity and stability of chemical species, including Latimer diagrams, Pourbaix diagrams, and Frost diagrams. Latimer diagrams show the standard reduction potential of oxidation states of an element using a horizontal line with values above it. Pourbaix diagrams represent the stability of a metal as a function of potential and pH, with different lines and boundaries indicating acid-base, redox, and solubility equilibria. Frost diagrams depict the free energy versus oxidation state of an element and can be constructed from Latimer diagrams. These diagramming methods provide a way to understand and predict the behavior of elements under various conditions.
The document discusses the lability and inertness of coordination complexes. It defines labile complexes as those where ligand exchange occurs rapidly, while inert complexes have slow ligand exchange. Lability is determined by factors like the metal ion size, charge, and d-electron configuration, not thermodynamic stability. Smaller or higher charged metal ions and complexes with less than 3 d-electrons tend to be more labile. The rate of ligand substitution depends on both the leaving and entering ligands. Steric effects and solvent also influence the rate. Complexes may undergo dissociative or associative substitution based on their structure.
This document discusses key concepts in electrochemistry including:
- Electrochemistry deals with chemical and physical processes involving the production or consumption of electricity.
- Electrode potential is the potential difference that exists between a metal and its ions in solution, arising from their relative tendencies to undergo oxidation or reduction reactions.
- Standard hydrogen electrode is used as a reference electrode to measure standard electrode potentials of other half-cells.
- Standard electrode potential of a half-cell indicates its voltage when connected to the standard hydrogen electrode under standard conditions.
- Electromotive force is the difference in potential between the cathode and anode half-cells of an electrochemical cell.
The selection rules that determine which electronic transitions are allowed or forbidden in transition metal complexes are the Laporte selection rule and spin selection rule. The Laporte rule forbids transitions that result in no change in orbital angular momentum, while the spin rule forbids transitions that change the overall spin of the complex. These rules can be relaxed by vibronic coupling in octahedral complexes or do not apply in tetrahedral complexes. Orbital contributions to paramagnetic moment only occur when the transition metal d orbitals are asymmetrically occupied, allowing electron circulation between degenerate orbitals.
This document discusses Hard and Soft Acids and Bases (HSAB) theory presented by Dr. Satish S. Kola. It defines characteristics of hard vs soft acids and bases, with hard acids/bases being small with high oxidation states and no d-electrons, while soft acids/bases are large with low oxidation states and many d-electrons. Applications of HSAB principles are discussed, including predicting complex formation and metal catalyst poisoning. The theoretical basis involves concepts like pi-bonding, electrostatic interactions, and polarizability. Limitations are noted where inherent acid/base strength may override HSAB predictions.
The video lecture for this presentation is available at the following link on YouTube
https://youtu.be/3sxal579RNM
The presenation will be useful for Ug/PG (Chemistry) students
This document discusses organometallic chemistry and is presented by Dr. Manju Sebastian. It describes the classification of organometallic compounds based on the type of metal-carbon bond formed. The classifications include ionic compounds, compounds with sigma bonds, compounds with pi bonds, and compounds with multicenter bonds. Examples are provided for each classification. Additional topics covered include carbonyl complexes, ferrocene, applications of organometallics as catalysts including the Ziegler-Natta and Wilkinson catalysts.
This document contains notes on physical chemistry unit 3 covering topics like conductance, equivalent and molar conductivity, Kohlrausch law, transport numbers and their experimental determination using Hittorf and moving boundary methods. It also discusses applications of conductance measurements like determination of degree of ionization of weak electrolytes, solubility of sparingly soluble salts, ionic product of water, and conductometric titrations.
This document discusses different types of diagrams used to represent the reactivity and stability of chemical species, including Latimer diagrams, Pourbaix diagrams, and Frost diagrams. Latimer diagrams show the standard reduction potential of oxidation states of an element using a horizontal line with values above it. Pourbaix diagrams represent the stability of a metal as a function of potential and pH, with different lines and boundaries indicating acid-base, redox, and solubility equilibria. Frost diagrams depict the free energy versus oxidation state of an element and can be constructed from Latimer diagrams. These diagramming methods provide a way to understand and predict the behavior of elements under various conditions.
The document discusses the lability and inertness of coordination complexes. It defines labile complexes as those where ligand exchange occurs rapidly, while inert complexes have slow ligand exchange. Lability is determined by factors like the metal ion size, charge, and d-electron configuration, not thermodynamic stability. Smaller or higher charged metal ions and complexes with less than 3 d-electrons tend to be more labile. The rate of ligand substitution depends on both the leaving and entering ligands. Steric effects and solvent also influence the rate. Complexes may undergo dissociative or associative substitution based on their structure.
This document discusses key concepts in electrochemistry including:
- Electrochemistry deals with chemical and physical processes involving the production or consumption of electricity.
- Electrode potential is the potential difference that exists between a metal and its ions in solution, arising from their relative tendencies to undergo oxidation or reduction reactions.
- Standard hydrogen electrode is used as a reference electrode to measure standard electrode potentials of other half-cells.
- Standard electrode potential of a half-cell indicates its voltage when connected to the standard hydrogen electrode under standard conditions.
- Electromotive force is the difference in potential between the cathode and anode half-cells of an electrochemical cell.
The selection rules that determine which electronic transitions are allowed or forbidden in transition metal complexes are the Laporte selection rule and spin selection rule. The Laporte rule forbids transitions that result in no change in orbital angular momentum, while the spin rule forbids transitions that change the overall spin of the complex. These rules can be relaxed by vibronic coupling in octahedral complexes or do not apply in tetrahedral complexes. Orbital contributions to paramagnetic moment only occur when the transition metal d orbitals are asymmetrically occupied, allowing electron circulation between degenerate orbitals.
This document discusses Hard and Soft Acids and Bases (HSAB) theory presented by Dr. Satish S. Kola. It defines characteristics of hard vs soft acids and bases, with hard acids/bases being small with high oxidation states and no d-electrons, while soft acids/bases are large with low oxidation states and many d-electrons. Applications of HSAB principles are discussed, including predicting complex formation and metal catalyst poisoning. The theoretical basis involves concepts like pi-bonding, electrostatic interactions, and polarizability. Limitations are noted where inherent acid/base strength may override HSAB predictions.
The video lecture for this presentation is available at the following link on YouTube
https://youtu.be/3sxal579RNM
The presenation will be useful for Ug/PG (Chemistry) students
This document discusses organometallic chemistry and is presented by Dr. Manju Sebastian. It describes the classification of organometallic compounds based on the type of metal-carbon bond formed. The classifications include ionic compounds, compounds with sigma bonds, compounds with pi bonds, and compounds with multicenter bonds. Examples are provided for each classification. Additional topics covered include carbonyl complexes, ferrocene, applications of organometallics as catalysts including the Ziegler-Natta and Wilkinson catalysts.
This document contains notes on physical chemistry unit 3 covering topics like conductance, equivalent and molar conductivity, Kohlrausch law, transport numbers and their experimental determination using Hittorf and moving boundary methods. It also discusses applications of conductance measurements like determination of degree of ionization of weak electrolytes, solubility of sparingly soluble salts, ionic product of water, and conductometric titrations.
1) Latimer, Frost, and Pourbaix diagrams are used to predict and summarize redox reactions in aqueous solutions. Latimer diagrams list standard potentials for step-wise reductions while Frost diagrams plot free energy vs oxidation state. Pourbaix diagrams show predominant species as a function of both potential and pH.
2) Latimer and Frost diagrams are restricted to pH 0 or 14 while Pourbaix diagrams cover the full pH range from 0-14. Pourbaix diagrams indicate the most stable species under given conditions and can identify strong oxidizers, reducers, and species prone to disproportionation.
3) These diagram types are useful tools for predicting thermodynamic favorability and identifying stable vs unstable oxidation states of
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
1. Localized bonds involve electron density concentrated between two nuclei, while delocalized bonds involve electron density spread across multiple nuclei.
2. Conjugated systems have alternating single and multiple bonds, allowing p-orbitals to overlap and form delocalized molecular orbitals spread across multiple atoms. This delocalization increases stability.
3. Examples given include the allyl radical and cation, which have three p-orbitals overlapping to form bonding and antibonding molecular orbitals delocalized across all three carbons. 1,3-Butadiene also has four overlapping p-orbitals forming delocalized molecular orbitals.
The document discusses migratory aptitude in rearrangement reactions. It defines migratory aptitude as the relative ability of a migrating group to migrate in a rearrangement reaction. Factors that affect migratory aptitude include the stability of the carbocation formed and the electron density of the migrating group. Aryl groups generally have higher migratory aptitude than alkyl groups. The document also describes different types of rearrangement reactions and the mechanisms of nucleophilic rearrangements.
This document discusses ligand substitution reactions in octahedral complexes. It describes the main mechanisms of ligand substitution including dissociative (SN1), associative (SN2), and concerted (interchange) pathways. It also discusses hydrolysis reactions and anation reactions as types of ligand substitutions. Specific examples are provided of acid and base hydrolysis in octahedral cobalt complexes, and factors that influence the reaction mechanisms and rates are outlined.
Coordination polymers are inorganic or organometallic polymers with repeating metal cation centers linked by organic ligands. They can extend in 1, 2, or 3 dimensions based on the metal's coordination number and geometry. Coordination polymers have many potential applications due to their tunable structures and properties. They are synthesized through self-assembly of metal salts and ligands, and their structures can be classified based on dimensionality and other factors. Important applications of coordination polymers include dyes, molecular storage, luminescence, electrical conductivity, and magnetism.
Stereo chemistry of substitute cyclohexane presentationMUKULsethi5
this video very useful for all chemistry related exam like
jee main+adwance
bsc
msc
iit jam
CSIR
gate
du
bhu
hcu
in this we discuss stereochemistry of substitute cyclohexane.
we discuss about
1,3 diaxal interaction
1,2 interaction
mono substitute cyclohexane
Conformation of Cyclohexane
Stereochemical configuration of cyclohexane
Newman projection of cyclohexane
Repulsion energy of substituent in cyclohexane
This presentation consists of three topics that are:
1. conductance of electrolytic solution
2. Specific Conductance, Molar Conductance & Equivalent Conductance
3. Kohlrausch's Law
This document discusses the application of conductance measurements in chemistry. It describes five uses: 1) determining the degree of dissociation of weak electrolytes, 2) determining ionization constants of acids, 3) determining solubility products of sparingly soluble salts, 4) calculating the ionic product of water, and 5) conductometric titration. Conductometric titration involves measuring conductivity during a titration to determine the endpoint, which occurs when conductivity remains constant as the neutralization point is reached. Factors that affect conductivity include the size, temperature, charge, and number of ions in solution.
The document discusses molecular orbital theory (MOT), an approach to bonding in which orbitals encompass the entire molecule rather than being localized between atoms. MOT was put forward by Hund and Mulliken and later modified by Jones and Coulson. It addresses some of the drawbacks of valence bond theory, including explaining the paramagnetic nature of O2. MOT uses the linear combination of atomic orbitals (LCAO) approach and Hund's rule to determine molecular orbital configurations and energies.
Lattice energy refers to the energy released when separate ions in the gas phase form an ionic crystal lattice. It can be calculated theoretically using the Born-Landé equation or experimentally using the Born-Haber cycle. The Born-Landé equation considers the electrostatic attraction and repulsive forces between ions, while the Born-Haber cycle uses standard enthalpy data and Hess's law. Lattice energy depends on factors like ion charge and size - higher charge or smaller ions lead to stronger electrostatic forces and higher lattice energy. Lattice energy is an important concept for understanding the properties and stability of ionic compounds.
This document discusses electronic displacement in organic compounds. It describes two types of electronic displacement: permanent displacement including inductive, resonance, and mesomeric effects; and temporary displacement through electromeric effects. Inductive effects are further broken down into +I effects where groups donate electron density and -I effects where groups withdraw electron density. Examples of inductive effects include their impact on acid/base strength, stability of carbocations/carbanions, and dipole moments.
The document discusses fullerenes, which are hollow carbon structures made of pentagons and hexagons. It provides a brief history of their discovery in 1985 and describes their structure as spheres like soccer balls made of 12 pentagons and various hexagons. The most famous fullerene is buckminsterfullerene (C60), which contains 60 carbon atoms arranged in 20 hexagons and 12 pentagons. The document outlines the hybridization, bonding, and geometry of C60 and other fullerenes. It concludes by discussing some applications of fullerenes in areas like antioxidants, drug delivery, solar cells, and more.
Electrochemistry is the study of chemical reactions caused by the passage of an electric current and the production of electrical energy from chemical reactions. It encompasses phenomena like corrosion and devices like batteries and fuel cells. Electrochemical cells are either electrolytic cells, where an external power source drives non-spontaneous reactions, or galvanic/voltaic cells, where spontaneous reactions produce electricity. The kinetics and rates of electrochemical reactions, as well as mass transfer of reactants, influence current production in fuel cells and other devices.
This document provides an overview of chemical kinetics and reaction rates. It discusses:
1) Chemical kinetics deals with how fast chemical reactions occur and the factors that affect reaction rates.
2) Reaction rates can vary significantly, from fractions of a second to years, as seen in examples of iron rusting and silver chloride formation.
3) The study of chemical kinetics involves determining rates of reaction, factors affecting rates, and reaction mechanisms.
It then provides examples and methods for determining reaction order and the effect of temperature on reaction rates.
HSAB concept is an initialism for "hard and soft (Lewis) acids and bases". Also known as the Pearson acid-base concept, HSAB is widely used in chemistry for explaining stability of compounds, reaction mechanisms and pathways.
This document provides an overview of electrochemistry concepts including:
(1) Electrolytes are substances that conduct electricity in solution via ion movement, while non-electrolytes do not conduct. Examples of each are given.
(2) Strong and weak electrolytes are described based on their degree of ionization. Common examples of each type are listed.
(3) Key differences between electronic and electrolytic conductors are outlined regarding how electricity flows through each type.
1) Latimer, Frost, and Pourbaix diagrams are used to predict and summarize redox reactions in aqueous solutions. Latimer diagrams list standard potentials for step-wise reductions while Frost diagrams plot free energy vs oxidation state. Pourbaix diagrams show predominant species as a function of both potential and pH.
2) Latimer and Frost diagrams are restricted to pH 0 or 14 while Pourbaix diagrams cover the full pH range from 0-14. Pourbaix diagrams indicate the most stable species under given conditions and can identify strong oxidizers, reducers, and species prone to disproportionation.
3) These diagram types are useful tools for predicting thermodynamic favorability and identifying stable vs unstable oxidation states of
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
1. Localized bonds involve electron density concentrated between two nuclei, while delocalized bonds involve electron density spread across multiple nuclei.
2. Conjugated systems have alternating single and multiple bonds, allowing p-orbitals to overlap and form delocalized molecular orbitals spread across multiple atoms. This delocalization increases stability.
3. Examples given include the allyl radical and cation, which have three p-orbitals overlapping to form bonding and antibonding molecular orbitals delocalized across all three carbons. 1,3-Butadiene also has four overlapping p-orbitals forming delocalized molecular orbitals.
The document discusses migratory aptitude in rearrangement reactions. It defines migratory aptitude as the relative ability of a migrating group to migrate in a rearrangement reaction. Factors that affect migratory aptitude include the stability of the carbocation formed and the electron density of the migrating group. Aryl groups generally have higher migratory aptitude than alkyl groups. The document also describes different types of rearrangement reactions and the mechanisms of nucleophilic rearrangements.
This document discusses ligand substitution reactions in octahedral complexes. It describes the main mechanisms of ligand substitution including dissociative (SN1), associative (SN2), and concerted (interchange) pathways. It also discusses hydrolysis reactions and anation reactions as types of ligand substitutions. Specific examples are provided of acid and base hydrolysis in octahedral cobalt complexes, and factors that influence the reaction mechanisms and rates are outlined.
Coordination polymers are inorganic or organometallic polymers with repeating metal cation centers linked by organic ligands. They can extend in 1, 2, or 3 dimensions based on the metal's coordination number and geometry. Coordination polymers have many potential applications due to their tunable structures and properties. They are synthesized through self-assembly of metal salts and ligands, and their structures can be classified based on dimensionality and other factors. Important applications of coordination polymers include dyes, molecular storage, luminescence, electrical conductivity, and magnetism.
Stereo chemistry of substitute cyclohexane presentationMUKULsethi5
this video very useful for all chemistry related exam like
jee main+adwance
bsc
msc
iit jam
CSIR
gate
du
bhu
hcu
in this we discuss stereochemistry of substitute cyclohexane.
we discuss about
1,3 diaxal interaction
1,2 interaction
mono substitute cyclohexane
Conformation of Cyclohexane
Stereochemical configuration of cyclohexane
Newman projection of cyclohexane
Repulsion energy of substituent in cyclohexane
This presentation consists of three topics that are:
1. conductance of electrolytic solution
2. Specific Conductance, Molar Conductance & Equivalent Conductance
3. Kohlrausch's Law
This document discusses the application of conductance measurements in chemistry. It describes five uses: 1) determining the degree of dissociation of weak electrolytes, 2) determining ionization constants of acids, 3) determining solubility products of sparingly soluble salts, 4) calculating the ionic product of water, and 5) conductometric titration. Conductometric titration involves measuring conductivity during a titration to determine the endpoint, which occurs when conductivity remains constant as the neutralization point is reached. Factors that affect conductivity include the size, temperature, charge, and number of ions in solution.
The document discusses molecular orbital theory (MOT), an approach to bonding in which orbitals encompass the entire molecule rather than being localized between atoms. MOT was put forward by Hund and Mulliken and later modified by Jones and Coulson. It addresses some of the drawbacks of valence bond theory, including explaining the paramagnetic nature of O2. MOT uses the linear combination of atomic orbitals (LCAO) approach and Hund's rule to determine molecular orbital configurations and energies.
Lattice energy refers to the energy released when separate ions in the gas phase form an ionic crystal lattice. It can be calculated theoretically using the Born-Landé equation or experimentally using the Born-Haber cycle. The Born-Landé equation considers the electrostatic attraction and repulsive forces between ions, while the Born-Haber cycle uses standard enthalpy data and Hess's law. Lattice energy depends on factors like ion charge and size - higher charge or smaller ions lead to stronger electrostatic forces and higher lattice energy. Lattice energy is an important concept for understanding the properties and stability of ionic compounds.
This document discusses electronic displacement in organic compounds. It describes two types of electronic displacement: permanent displacement including inductive, resonance, and mesomeric effects; and temporary displacement through electromeric effects. Inductive effects are further broken down into +I effects where groups donate electron density and -I effects where groups withdraw electron density. Examples of inductive effects include their impact on acid/base strength, stability of carbocations/carbanions, and dipole moments.
The document discusses fullerenes, which are hollow carbon structures made of pentagons and hexagons. It provides a brief history of their discovery in 1985 and describes their structure as spheres like soccer balls made of 12 pentagons and various hexagons. The most famous fullerene is buckminsterfullerene (C60), which contains 60 carbon atoms arranged in 20 hexagons and 12 pentagons. The document outlines the hybridization, bonding, and geometry of C60 and other fullerenes. It concludes by discussing some applications of fullerenes in areas like antioxidants, drug delivery, solar cells, and more.
Electrochemistry is the study of chemical reactions caused by the passage of an electric current and the production of electrical energy from chemical reactions. It encompasses phenomena like corrosion and devices like batteries and fuel cells. Electrochemical cells are either electrolytic cells, where an external power source drives non-spontaneous reactions, or galvanic/voltaic cells, where spontaneous reactions produce electricity. The kinetics and rates of electrochemical reactions, as well as mass transfer of reactants, influence current production in fuel cells and other devices.
This document provides an overview of chemical kinetics and reaction rates. It discusses:
1) Chemical kinetics deals with how fast chemical reactions occur and the factors that affect reaction rates.
2) Reaction rates can vary significantly, from fractions of a second to years, as seen in examples of iron rusting and silver chloride formation.
3) The study of chemical kinetics involves determining rates of reaction, factors affecting rates, and reaction mechanisms.
It then provides examples and methods for determining reaction order and the effect of temperature on reaction rates.
HSAB concept is an initialism for "hard and soft (Lewis) acids and bases". Also known as the Pearson acid-base concept, HSAB is widely used in chemistry for explaining stability of compounds, reaction mechanisms and pathways.
This document provides an overview of electrochemistry concepts including:
(1) Electrolytes are substances that conduct electricity in solution via ion movement, while non-electrolytes do not conduct. Examples of each are given.
(2) Strong and weak electrolytes are described based on their degree of ionization. Common examples of each type are listed.
(3) Key differences between electronic and electrolytic conductors are outlined regarding how electricity flows through each type.
This document discusses electrochemistry and key concepts related to conductivity of electrolyte solutions. It defines electrochemistry as the study of chemical reactions caused by electricity or electrical energy and the conversion between chemical and electrical energy. It describes how conductivity is measured and how it varies with concentration, temperature, and other factors for strong and weak electrolytes. The document also discusses concepts such as molar conductivity, transport numbers, solubility products, and the Debye-Hückel theory of ionic interactions.
1. Electrochemistry deals with the production of electricity from chemical reactions and use of electricity to cause non-spontaneous reactions.
2. Conductors are classified as metallic conductors which allow current by electron movement and electrolytic conductors which allow current through dissolved or molten state with chemical decomposition.
3. Electrolytes are classified as strong which completely dissociate and weak which partially dissociate. Conductivity is directly proportional to concentration and inversely proportional to length.
1. Electrolyte solutions conduct electricity due to the presence of ions. Strong electrolytes fully dissociate into ions in solution, while weak electrolytes only partially dissociate.
2. Ion transport in electrolyte solutions occurs through diffusion due to concentration gradients and migration due to applied electric fields. Conductivity and molar conductivity describe how well solutions conduct, and depend on factors like ion type and concentration.
3. At infinite dilution, the limiting molar conductivity of electrolytes can be calculated from the ion mobilities. For concentrated solutions, effects like ion-ion interactions cause conductivity to decrease with concentration.
This document provides information on electrochemistry and electrochemical cells. It defines electrochemistry as the study of electricity production from spontaneous chemical reactions and use of electrical energy for non-spontaneous reactions. It describes different types of electrochemical cells including galvanic cells that convert chemical to electrical energy and electrolytic cells that do the opposite. Key concepts discussed include electrode potentials, standard hydrogen electrode, Nernst equation, and factors affecting cell potential. Common electrochemical devices like batteries and the corrosion process are also summarized.
Conductance of electrolyte solution, specific, equivalent and molar conductance. Determination conductance of electrolyte solution, Cell constant its determination and problems
Introduction to Electrochemistry
- Electrochemistry explores the interplay between electrical energy and chemical reactions, focusing on oxidation-reduction (redox) reactions and electrochemical cells.
**Oxidation and Reduction**
- Oxidation involves the loss of electrons, while reduction involves the gain of electrons, summed up by the mnemonic OIL RIG. An example reaction is Zn + Cu²⁺ → Zn²⁺ + Cu.
**Redox Reactions in Everyday Life**
- Examples include the rusting of iron, cellular respiration, and the combustion of fuels.
**Electrochemical Cells**
- Two main types are Galvanic (Voltaic) cells, which convert chemical energy into electrical energy, and Electrolytic cells, which use electrical energy to drive chemical reactions. Components include the anode (where oxidation occurs), the cathode (where reduction occurs), and an electrolyte.
**Galvanic Cells**
- A common example is the Daniell Cell, which generates electrical energy through spontaneous redox reactions.
**Electrolytic Cells**
- These cells drive non-spontaneous reactions using electrical energy, such as the electrolysis of water to produce hydrogen and oxygen gases.
**Applications of Electrochemistry**
- Includes batteries (e.g., lithium-ion, alkaline), electroplating, corrosion prevention methods like galvanization, and fuel cells that directly convert chemical energy into electrical energy.
**Electrochemistry in Nature**
- Involves biochemical processes like the electron transport chain in mitochondria and natural galvanic cells, such as those influenced by lightning in soil.
**Summary**
- Understanding redox reactions and electrochemical cells is essential. Electrochemistry has a wide range of practical applications, making it a significant field of study.
**Discussion and Q&A**
- Engage with the audience to explore real-life applications and recent advancements in electrochemistry.
This summary encapsulates the key points and themes of the presentation, providing a concise overview of the fundamental concepts and applications of electrochemistry.
1) Electrochemistry deals with interconversion of electrical and chemical energy. In batteries, chemical energy is converted to electrical energy, while in electrolysis and electroplating, electrical energy is converted to chemical energy.
2) Conductors allow electric current to pass through them. Metallic conductors conduct via electrons, while electrolytic conductors conduct via ions when in solution or molten state.
3) Concentration cells produce electrical energy from differences in concentration of electrolytes or electrodes in two half-cells, without an overall chemical reaction. The cell potential can be calculated from Nernst's equation and depends on the log of the concentration ratio.
This document is a chemistry project report submitted by Ayushi Gupta of Class XII. The project discusses the conductance of electrolytic solutions. It defines electrolytes and explains that they conduct electricity in solution due to the ions formed. It then discusses various topics related to conductivity of electrolytes like specific conductivity, equivalent conductivity, molar conductivity, and their relationships. It also describes how conductivity of electrolytic solutions is measured using a conductivity cell and Wheatstone bridge. Kohlrausch law relating limiting molar conductivity of electrolytes to their constituent ions is also explained.
This document discusses conductometry, which is a method of analysis based on measuring the electrolytic conductance of a solution. It begins by classifying different electrochemical methods, including conductometry and electrophoresis which do not involve redox reactions. It then discusses key concepts in conductometry such as conductivity, conductance, equivalent conductance, and how various factors like ion nature, temperature, concentration, and electrode size affect conductance. It also provides examples of calculating conductance and equivalent conductance from experimental measurements. Instrumentation for conductometric determination includes a conductance cell and conductivity bridge.
Electrochemistry involves the study of electricity produced from spontaneous chemical reactions in galvanic cells and the use of electricity to drive non-spontaneous reactions in electrolytic cells. Galvanic cells produce electricity through spontaneous redox reactions, with oxidation occurring at the anode and reduction at the cathode. Electrolytic cells use electricity to carry out non-spontaneous reactions. The potential difference between electrodes in a galvanic cell is called the cell potential, which can be calculated using standard electrode potentials and concentrations based on the Nernst equation.
This document provides information on various topics in electrochemistry. It defines electrolytes and non-electrolytes, and discusses different types of conductors. It also explains electrochemical cells and electrolytic cells. Key concepts covered include electrode potential, the electrochemical series, Faraday's laws of electrolysis, and different types of batteries.
Introduction
Ohm’s law.
Conductometric measurements.
Factor affecting conductivity.
Application of conductometry.
2.Conductometric titration-:
Introduction.
Types of conductometric tiration.
Advantages of conductometric tiration.
3.Recent devlopement
Conductometry:
is the simplest of the electroanalytical techniques; by Kolthoff in 1929.
Conductors are:
either metallic (flow of electrons) or electrolytic (movemenmt of ions).
Conductance of electricity:
migration of positively charged ions towards the cathode and negatively charged ones towards the anode
(i.e.) current is carried by all ions present in solution.
Conductance depends on the number of ions in solun.
Factors affecting conductance:
1- Temperature:
(1C increase in temperature causes 2 % increase in conductance).
2- Nature of ions
Size, molecular weight and number of charges.
3- Concentration of ions:
As the number of ions increases, the conductance increases.
4- Size of electrodes
Conductance is directly proportional to the cross sectional area (A).
The document discusses various topics in electrochemistry including: ionic motion in electrolytic conduction; electrolytes and electrolysis; electrolytic cells; conductance; specific conductance; equivalent conductance; molar conductance; variation of molar conductance with dilution; ionic mobility; Faraday's laws of electrolysis; and Ohm's law as applied to electrolytic conductors. It also describes migration of ions and the factors that influence ionic mobility such as size, charge, hydration, and temperature.
Beaker A contained 0.74 g Ca(OH)2 in 100 ml water. This amount is less than the saturation point of 0.0814 g/100 ml. So the solution was unsaturated.
Beaker B contained 1.48 g Ca(OH)2 in 100 ml water. This amount exceeds the saturation point. So the solution was saturated.
The conductivity and pH would be higher in the saturated solution in Beaker B compared to the unsaturated solution in Beaker A. This is because in a saturated solution, more Ca2+ and OH- ions are available to carry current and increase pH respectively.
So the solution in Beaker B would be more conductive and have a higher pH value than
1. The document discusses electrolytes and their conductivity properties. It defines strong and weak electrolytes and gives examples of each.
2. Kohlrausch's law of independent migration of ions states that at infinite dilution, each ion in an electrolyte contributes a characteristic value to the molar conductivity that is independent of the other ions present.
3. The document outlines several applications of Kohlrausch's law, including determining the degree of ionization of weak electrolytes, calculating ionization constants, and determining the ionic product of water and solubility products of sparingly soluble salts.
This document discusses conductometric titration, which is an electrochemical analytical method that measures the electrical conductance of an electrolyte solution. It describes the principles and instrumentation of conductometry, including how conductivity is measured using a conductivity meter or by performing a titration. Some key applications of conductometric titration are determining the end point of acid-base and precipitation titrations, and it has various uses in fields like environmental analysis, food testing, and quality control.
Similar to Electrochemistry (part ii) class xii (20)
Importance of amines, classification of amines, Preparation of amines, Physical properties, Chemical properties, Basic nature, tests of amines, Carbylamine test, Hinsberg's test, reactions with nitrous acid, electrophilic reactions, -NH2 group protection, Diazonium salts, Uses, Some important conversions, short questions with answers.
Contents: Intermolecular forces, Thermal energy vs intermolecular forces, The gaseous state, The gas laws, Boyl's law, Charle's law, Gay Lussac's law, Avogadro's law, Absolute temperature, STP. Ideal gas equation, Units og 'R', Numerical problems, Dalton's law of partial pressure, Kinetic theory of gases, Deviation from ideal gas behavior- real gas or non-ideal gas, van der Waals equation, significance of 'a' & 'b', Compressibility factor (Z)
Introduction, position in periodic table, transition elements & inner transition elements, lanthanoids & actinoids, General trends in properties, atomic radii, atomic volume, melting points, boiling points, density, standard electrode potentials, oxidation states, Some practice questions.
This is the power point presentation for the students of class XII. This includes: Types of solutions, concentration of solutions, Solution of solid in liquid, solution of gas in liquid: Henry's law, vapour pressure of solutions, Raoult's law, Ideal & non ideal solutions, azeotropic mixtures, Colligative properties - (1) relative lowering of vapour pressure of solution of volatile solute, (2) elevation in boiling point of solution (3) depression in freezing point of solution (4) osmotic pressure, abnormal molar mass of solute, Van't Hoff's factor, numerical problems.
This unit includes: rate of a chemical reaction, graphs,, unit of rate, average rate& instantaneous rate,. factors influuncing rate of a reaction, Rate expression & rate constant, Order & molecularity of a reaction,, initiall rate method & integrated rate law equations, numerical problems,, Half life period, Pseudo first order reaction, Temperature of rate of reaction, Activation energy, collision frequency & effective collision, Collision theory, Arrhenius equation,, effect of catalyst on rate of reaction, numerical problems
Class xi unit 1 some basic concepts of chemistryArunesh Gupta
The chapter includes- importance of chemistry,nature of matter, classification of matter,measurement of matter,SI unit, mass, volume density, length, temperature, uncertainty in measurement, Scientific notation, Significant figures, Dimensional analysis, Laws of chemical combinations,- law of conservation of mass, law of definite proportion,law of multiple proportion, Gay Lussac law, Avogadro law, Dalton's atomic theory, Atomic mass, average atomic mass, molecular mass Formula mass, mole concept % composition,Empirical & molecular formula, Stoichiometric calculations, limiting reagent, Concentration of solution & reaction, Mass %, volume %, mole fraction. molarity, molality
Class XII d and f- block elements (part 2)Arunesh Gupta
This part contains ionisation enthalpies, oxidation states, metal oxides & oxocations, magnetic properties, coloured ions of d block elements, catalysts, interstitial compounds, alloy formation & some important conceptual questions with answers as hints. Also some reasoning questions are given to test the understanding of properties of d block elements.
CONTENTS
Electrochemistry: definition & importance
Conductors: metallic & electrolytic conduction,
Electrolytes, Electrochemical cell & electrolytic cell
A simple electrochemical cell: Galvanic cell or (Daniell Cell)
Cell reaction, cell representation, Salt bridge & its use,
Electrode potential, standard electrode potential, SHE,
Standard cell potential or standard electromotive force of a cell
Electrochemical series (Standard reduction potential values)
Nernst Equation, Relationship with Standard cell potential with Gibbs energy & also equilibrium constant
Resistance (R) & conductance (G) of a solution of an electrolyte
Conductivity (k) of solution, Cell constant (G*) & their units,
Molar conductivity (Λm) & its variation with concentration & temperature,
Debye Huckel Onsager equation & Limiting molar conductivity,
Kohlrausch’s law & its application & numerical problems.
Electrolytic cells & electrolysis.
Some examples of electrolysis of electrolytes in molten / aq. state.
Faraday’s laws of electrolysis: First & second law- numerical problems. Corrosion, Electrochemical theory of rusting.
Prevention of rusting.
Class XII Electrochemistry - Nernst equation.Arunesh Gupta
This document provides an overview of electrochemistry and some key concepts. It begins by defining electrochemistry as the study of how spontaneous chemical reactions can produce electricity and how electrical energy can drive non-spontaneous reactions. It then discusses several applications of electrochemistry including metal production, electroplating, and batteries. The document goes on to define conductors and the differences between metallic and electrolytic conduction. It also introduces concepts like galvanic cells, salt bridges, standard electrode potentials, and the electrochemical series. In summary, the document provides a broad introduction to fundamental electrochemistry topics and concepts.
This presentation is for the professionals particularly teachers to have professionalism in work place. His / her attitude should be within a frame with ethics. His / her conduct should be examplaryfor all others to follow, best for the organisation
This document discusses chemical equilibrium, including definitions, characteristics, and factors that affect equilibrium. It defines chemical equilibrium as a state where the forward and reverse reaction rates are equal. Characteristics include the dynamic nature of equilibrium and constant concentrations of reactants and products at equilibrium. Factors that affect equilibrium position include concentration, pressure, temperature, and catalyst additions according to Le Chatelier's principle. The relationship between the equilibrium constant K and standard Gibbs free energy change ΔG° is also described.
A homogeneous thermodynamic system is one whose properties are uniform throughout. A heterogeneous system contains distinct phases.
There are several types of thermodynamic processes including isochoric (constant volume), isobaric (constant pressure), and adiabatic (no heat transfer). Extensive properties depend on amount of substance and intensive properties do not.
The first law of thermodynamics states that energy is conserved and heat and work are equivalent. For an ideal gas undergoing an adiabatic process, PVγ is constant, where γ is the heat capacity ratio.
Concept on Ellingham diagram & metallurgyArunesh Gupta
Ellingham Diagram decides the better reducing agent for metallurgy at different temperature, considering the Standard Free energy change of oxidation per mole of oxygen with temperature. It takes into consideration that for a reaction to be feasible, ∆rG < 0 or negative.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
This presentation was provided by Rebecca Benner, Ph.D., of the American Society of Anesthesiologists, for the second session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Two: 'Expanding Pathways to Publishing Careers,' was held June 13, 2024.
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
Iván Bornacelly, Policy Analyst at the OECD Centre for Skills, OECD, presents at the webinar 'Tackling job market gaps with a skills-first approach' on 12 June 2024
Elevate Your Nonprofit's Online Presence_ A Guide to Effective SEO Strategies...TechSoup
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1. ELECTROCHEMISTRY (PART 2)
CLASS XII
BY: ARUNESH GUPTA
PGT (CHEMISTRY)
KENDRIYA VIDYALAYA, BARRACKPORE (AFS)
Sub-topics: Resistance (R) & conductance (G) of a solution of an electrolyte, Conductivity (k) of solution,
factors affecting conductivity, Cell constant (G*) & its unit, Molar conductivity (Λm) & its variation with
concentration & temperature Numerical problems based on G, k, & Λm , Debye Huckel Onsager equation.
Limiting molar conductivity, Kohlrausch’s law of independent migration of ions, Its application & numerical
problems.
2. ELECTROCHEMISTRY
• Contents:
• Resistance (R) & conductance (G) of a solution of an electrolyte
• Conductivity (k) of solution,
• factors affecting conductivity,
• Cell constant (G*) & its unit,
• Molar conductivity (Λm) & its variation with concentration & temperature,
• Numerical problems based on G, k, & Λm ,
• Debye Huckel Onsager equation.
• Limiting molar conductivity,
• Kohlrausch’s law of independent migration of ions,
• Its application & numerical problems.
3. Conductance (G) (or electrolytic conductance)
It is the ease of flow of electric current through the conductor.
It is reciprocal of resistance (R).
G =
1
𝑅
Unit of G is ohm-1, mho, S, 𝛺−1
. (S denotes seimens)
(i) Ohm’s law:” the strength of current(I) is directly proportional to the potential
difference applied across the conductor & inversely proportional to the
resistance of the conductor. We can directly write: V = I R
(ii) Resistivity ( 𝝆) of a conductor is its resistance of 1 cm length & having area of
cross section to 1 cm2.
R = 𝝆
𝒍
𝒂
or. 𝝆 = 𝑹
𝒂
𝒍
Unit of resistivity = ohm cm or 𝜴 𝒄𝒎
SI unit of resistivity = 𝜴 𝒎
4. Conductivity (k) is defined as the conductance of a Solution if 1 cm length and having
1 sq. cm as the area of cross section. (k kappa)
Conductivity is the conductance of 1cm3 of a solution of an electrolyte.
Conductivity of a solution is the reciprocal of resistivity of a solution of an electrolyte.
K =
𝟏
𝝆
or k =
𝟏
𝑹
𝟏
𝒂
𝒍
k = G.G* where cell constant G* =
𝒍
𝒂
.
Unit of cell constant is cm-1 or m-1 (SI unit)
5. Conductivity
The unit of conductivity (k) of a solution in S cm-1 or S m-1
Here 1 S m-1 = 10-2 S cm-1.
Different materials have different conductivity (k) values.
Conductance (G) of a solution increases on dilution (ie. by adding water) but its
conductivity (k) decreases, as number of ions per unit volume decreases on
dilution.
Molar Conductivity (Λm)
The conductivity of all the ions produced when 1 mole of an electrolyte is
dissolved in V mL of solution is known as molar conductivity.
It is the conductance of 1 mole of an electrolyte placed between two electrodes 1
cm apart having V cm2 area of cross section.
It is related to conductance as Λm =
𝟏𝟎𝟎𝟎 𝒌
𝑴
where M is the molarity of solution
of electrolyte in mol L-1. It units are Ω-1 cm2 mol-1 or S m2 mol-1 (in SI unit).
Also, 1 S m2 mol-1 = 102 S cm2 mol-1
6. # We know that conductance of a solution of 1 cm3 is G
& conductance of 1 mole of V cm3 solution is Vk which is the definition of molar
conductivity.
Hence 𝛬 𝑚 = Vk.
Let the concentration of solution is M molar,
so, M mole of electrolyte is dissolved in 1 L = 1000 cm3 solution.
Hence, 1 mole of electrolyte is dissolved in
1000
𝑀
cm3 of solution = V cm3 of solution.
So, 𝛬 𝑚 = V.k or, 𝜦 𝒎 =
𝟏𝟎𝟎𝟎 𝒌
𝑴
# Unit of 𝜦 𝒎 =
𝑺𝒎−𝟏
𝒎𝒐𝒍 𝑳−𝟏 =
𝑺𝒎−𝟏
𝒎𝒐𝒍 𝒎−𝟑 𝟏𝟎 𝟑 So, S.I. unit of 𝜦 𝒎 is S m2 mol-1.
# With the increase of temperature, G, k & 𝛬 𝑚 increases.
# With the decrease in concentration on dilution, G increases, k decreases but
𝛬 𝑚 increases.
Molar conductivity
7. Numerical Problems:
Examples: (1) The resistance of a conductivity cell containing 0.001 M KCl solution at 298 K is
1500 Ω. What is the cell constant f conductivity of 0.001 M KCl solution at 298 K is 0.146 x 10-3 S
cm-1?
Solution: Given k = 0.146 x 10-3 S cm-1 & R = 1500 Ω We know, G = 1/R & k = GG* =
𝐺∗
𝑅
or,
G* = k.R = 0.146 x 10-3 x 1500 Hence G* = 0.219 cm-1 (Ans)
(2) A 0.05 M NaOH solution : a resistance of 31.6 ohm in a conductivity cell at 298 K. If area of
plates of conductivity cell is 3.8 cm2 & distance between them is 1.4 cm, calculate the molar
conductivity of NaOH solution.
Solution: Cell constant G* = l/a =
1.4 𝑐𝑚
3.8 𝑐𝑚2 = 0.368 cm-1. Given concentration = 0.05M, R = 31.6
ohm,
So, conductivity k = GG* =
𝐺∗
𝑅
=
0.368
31.6
– 0.0116 S cm-1. Hence, 𝛬 𝑚 =
1000 𝑘
𝑀
=
1000 𝑥 0.0116
0.05
= 232 S cm2
mol-1 (Ans)
(3) A conductivity cell when filled with 0.01 M KCl has a resistance of 747.5 ohm at 298K. When
the same cell was filled with an aqueous solution of 0.005 M CaCl2 solution, the resistance was
876 ohm. Calculate (i) conductivity and (ii) molar conductivity of CaCl2 solution. ( conductivity of
0.01 M KCl solution is 0.14114 S/m.
Solution: (a) For KCl solution: R = 747.5 ohm k = 0.14114 S/m
Hence Cell constant G* = R. k = 747.5 x 0.14114 = 105.5 m-1.
(b) For CaCl2 solution, conductivity cell is same. So cell constant (G*) is same.
Hence, conductivity k =
𝑐𝑒𝑙𝑙 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
=
105.5
= 0.1204 S/m
8. Numerical problems for practice:
(1) The molar conductivity of a 1.5 M solution of an electrolyte is found to be 138.9 S cm2mol-
1. Calculate the conductivity of this solution. [Ans: 0.2083
S/cm]
(2) The conductivity of a solution containing 1.0 g of anhydrous BaCl2 in 200 mL of the
has found to 0.0058 Scm-1. Calculate the molar conductivity of the solution. (At. No. Ba = 137,
Cl = 35.5)
[ Ans241.67 Scm2mol-1]
(3) The resistance of a conductivity cell with 0.1 M KCl solution is found to be 200 ohm at 298
K. When the same cell was filled with 0.02 M NaCl solution, the resistance at the at the same
temperature is found to be 1100 ohm. Calculate (i) cell constant of the cell in m-1.
. (ii) the molar
conductivity of 0.02 M NaCl solution in S m2 mol-1. (k for 0.1 M KCl solution at 298 K = 1.29
S/m)
[Ans: 258 m-1, 1.175 x 10-2 S m2 mol-1]
(4) The molar conductance of 0.05 M solution of MgCl2 is 194.5 S cm2 mol-1 at 298 K. A cell
electrodes having 1.50 cm2 surface area and 0.50 cm apart is filled with 0.05 M solution of
MgCl2. How much current will flow when the potential difference between the electrodes is 5
V? [Ans. 0.146 A]
9. Variation of molar conductivity with concentration for strong electrolytes.
In case of a strong electrolyte, molar conductivity increases slowly on dilution. On further
dilution till infinite dilution when concentration tends to zero , molar conductivity value
becomes a constant value for a particular electrolyte.
The molar conductivity when the concentration approaches zero is called molar conductivity
infinite dilution (𝛬 𝑚
𝑜
) or limiting molar conductivity
We can say, 𝛬 𝑚 = 𝛬 𝑚
𝑜
when molar concentration C tends to zero.
Debye-Huckel Onsager equation :
It gives a relation between molar conductivity, Λm at a particular concentration
and molar conductivity at infinite dilution 𝛬 𝑚
𝑜 . Mathematically, Λm = Λ0
m –
A√C
where, A is a constant. It depends upon the nature of solvent and
temperature.
10. 𝛬 𝑚
𝑜
𝛬 𝑚
𝑜
Debye-Huckel Onsager equation
Here, 𝛬 𝑚 = -A√C - 𝛬 𝑚
𝑜 (compare with
straight line eqn. y = mx + c
where Slope = -A and
y-intercept = 𝛬 𝑚
𝑜
,
The limiting value, Λ0
m or Λ∞
m.
(the molar conductivity at zero
concentration (or at infinite dilution)
can be obtained extrapolating the
graph. (Λ0
m is called limiting molar
conductivity).
11. Factors Affecting Conductivity :
(i) Nature of electrolyte
The strong electrolytes like KNO3 KCl. NaOH. etc. are completely ionised
in aqueous solution and have high values of molar conductivity.
The weak electrolytes are ionised to a lesser extent in aqueous solution
and have lower values of molar conductivity.
ii) Concentration of the solution
The concentrated solutions of strong electrolytes have significant
interionic attractions. which reduce the speed of ions and lower the
value of Λm.
The dilution decreases such attractions and increase the value of Λm.
12. Variation of molar conductivity (Λ0
m) with concentration of solution of weak electrolytes:
In case of weak electrolytes, the degree of ionisation
increases dilution which increases the value of Λ m. The
limiting value Λ0
m (limiting molar conductivity) cannot be
obtained by extrapolating the graph. The limiting value,
Λ0
m for weak electrolytes is obtained by Kohlrausch law
of independent migration of ions:
“At infinite dilution, the limiting molar conductivity of an
electrolyte is the sum of the limiting ionic conductivities of
all the cations and anions.”
e.g., for AxBy x Ay+ + y Bx-
Here 𝚲 𝐦
𝐨
𝐀 𝐱 𝐁 𝐲 = 𝐱𝛌 𝐀 𝐲+
𝐨
+ 𝐲𝛌 𝐁 𝐲−
𝐨
For weak electrolyte CH3COOH → CH3COO- + H+
𝚲 𝐦
𝐨 (𝐂𝐇 𝟑 𝐂𝐎𝐎𝐇) = 𝛌 𝐂𝐇 𝟑 𝐂𝐎𝐎−
𝐨
+ 𝛌 𝐇+
𝐨
13. Variation of molar conductivity with Temperature:
The increase of temperature decreases inter-
attractions of ions in the solution of an electrolyte and
increases kinetic energy of ions and their speed. Thus,
molar conductivity (Λm ) increase with temperature.
14. Applications of Kohlrausch law of independent migration of ions:
(i) We can determine the molar conductivities of weak electrolytes at infinite dilution, e.g.,
𝛬 𝑚
𝑜 𝐶𝐻3 𝐶𝑂𝑂𝐻 = 𝛬 𝑚
𝑜 𝐶𝐻3 𝐶𝑂𝑁𝑎 + 𝛬 𝐻𝐶𝑙
𝑜
− 𝛬 𝑁𝑎𝐶𝑙
𝑜
𝛬 𝑚
𝑜
(𝑁𝐻4 𝑂𝐻) = 𝛬 𝑚
𝑜
𝑁𝐻4 𝐶𝑙 + 𝛬 𝑁𝑎𝑂𝐻
𝑜
− 𝛬 𝑁𝑎𝐶𝑙
𝑜
(ii) Determination of degree of dissociation (α) of an electrolyte at a given dilution.
𝝰 =
𝒎𝒐𝒍𝒂𝒓 𝒄𝒐𝒏𝒅𝒖𝒄𝒕𝒊𝒗𝒊𝒕𝒚 𝒂𝒕 𝒂 𝒄𝒐𝒏𝒄𝒆𝒏𝒕𝒓𝒂𝒕𝒊𝒐𝒏 𝑪
𝒎𝒐𝒍𝒂𝒓 𝒄𝒐𝒏𝒅𝒖𝒄𝒕𝒊𝒗𝒊𝒕𝒚 𝒂𝒕 𝒊𝒏𝒇𝒊𝒏𝒊𝒕𝒆 𝒅𝒊𝒍𝒖𝒕𝒊𝒐𝒏 (𝒍𝒊𝒎𝒊𝒕𝒊𝒏𝒈 𝒎𝒐𝒍𝒂𝒓 𝒄𝒐𝒏𝒅𝒖𝒄𝒕𝒊𝒗𝒊𝒕𝒚)
or 𝝰 =
𝜦 𝒎
𝜦 𝒎
𝒐
The dissociation constant (Kc) of the weak electrolyte (of type AB) at concentration C of
the solution can be calculated by using the formula Kc =
𝑪𝜶 𝟐
𝟏− 𝜶
where, α is the degree of dissociation of the electrolyte.
15. Applications of Kohlrausch law of independent migration of ions:
(iii) Salts like BaSO4, PbSO4, AgCl, AgBr, AgI etc which do not dissolve
to a large extent in water are called sparingly soluble salts.
The solubility of a sparingly soluble salt can be calculated
as 𝜦 𝒎
𝒐 =
𝟏𝟎𝟎𝟎 𝒌
𝑺
where S is the solubility of a salt in mol/L.
Example: (1) The limiting molar conductivities of NaCl, NaAc & HCl are 126.4, 425.9 and 91.0 S
cm2 mol-1 respectively. Calculate the limiting molar conductivity of AcH.
Solution: ΛAcH
o
= λAc−
o
+ λH+
o
= λAc−
o
+ λNa+
o
+ λH+
o
+ λCl−
o
− λNa+
o
− λCl−
o
= ΛNaAc
0
+
ΛHCl
0
− ΛNaCl
0
= 425.9 + 91.0 – 126.4 = 226.0 S cm2 mol-1 (Ans)
Example (2) The conductivity (k) of 0.001028 M acetic acid is 4.95 x 10-5 S cm-1. Calculate its
dissociation constant if limiting molar conductivity is acetic acid is 390.5 S cm2 mol-1.
Solution: We know, Λm =
1000 𝑘
𝑀
=
1000 𝑥 4.95 𝑥 10−5
0.001028
= 48.15 S cm2mol-1.
Degree of dissociation 𝝰 =
𝛬 𝑚
𝛬 𝑚
𝑜 =
48.15
390.5
= 0.1233
And dissociation constant Kc =
𝐶𝛼2
1− 𝛼
0.001028 𝑥 (0.1233)2
1−0.1233
= 1.78 x 10-5 mol L-1 (Ans)
16. Numerical problems for practice: (from Kohlrausch’s law)
(1) Suggest a way to determine limiting molar conductivity of water.
[Ans: 𝛬 𝐻2 𝑂
0
= 𝛬 𝑁𝑎𝑂𝐻
0
+ 𝛬 𝐻𝐶𝑙
0
− 𝛬 𝑁𝑎𝐶𝑙
0
]
(2) The molar conductivity of of 0.025 M HCOOH is 46.1 S cm2 mol-1.
Calculate its degree of dissociation & dissociation constant.
(Given: 𝜆 𝐻+
𝑜
= 349.6 S cm2 mol-1 & 𝜆 𝐻𝐶𝑂𝑂−
𝑜
= 54.6 S cm2 mol-1.
[Ans: 0.114, 3.67 x 10-4]
(3) The molar conductivity at infinity dilution of aluminium sulphate is 858
S cm2 mol-1. Calculate the limiting molar ionic conductivity of Al3+ ion.
(Given 𝜆 𝑆𝑂4
2−
0
= 160 S cm2 mol-1. [Ans. 189 Scm2
(4) The limiting molar conductivity of NaOH, NaCl and BaCl2 at 298K are
2.481 x 10-2, 1.265 x 10-2 and 2.80 x 10-2 S cm2 mol-1 respectively. Calculate
𝛬 𝑚
𝑜 for Ba(OH)2. [Ans 5.23 x 10-2 S
mol-1]