To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
Reference electrodes are used to maintain a constant potential against which the potential of an indicator or working electrode can be measured. An ideal reference electrode has a reproducible and stable potential that is not affected by small currents or changes in temperature or solution composition. Common reference electrodes include the standard hydrogen electrode, which defines zero potential, and silver/silver chloride electrodes. Reference electrodes are used along with indicator or working electrodes in electrochemical cells to measure the potential difference between the electrodes, which depends on the analyte concentration.
This document discusses oxidation-reduction (redox) reactions. It defines oxidation as the loss of electrons and reduction as the gain of electrons. Redox reactions always involve a transfer of electrons between reactants. The key principles are:
1. Oxidation and reduction always occur together in a redox reaction.
2. The total number of electrons lost must equal the total number of electrons gained to satisfy the conservation of charge.
3. Redox titrations can be used to determine the concentration of an unknown substance and rely on a redox reaction between a titrant and analyte with an indicator or potentiometer used to find the endpoint.
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.
This document discusses the principles and methods of voltammetry and polarography. Some key points:
- Voltammetry measures the current-potential curve during electrolysis using a small amount of sample. Polarography uses a dropping mercury electrode as the working electrode.
- In polarographic analysis, a polarized working electrode and depolarized reference electrode are used. No stirring is used. Only a small amount of analyte undergoes electrolysis.
- The limiting diffusion current is proportional to analyte concentration and can be used for quantitative analysis. The half-wave potential is used for qualitative analysis.
- Factors like temperature, supporting electrolyte composition, and mercury electrode potential affect the limiting diffusion current.
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.
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
Reference electrodes are used to maintain a constant potential against which the potential of an indicator or working electrode can be measured. An ideal reference electrode has a reproducible and stable potential that is not affected by small currents or changes in temperature or solution composition. Common reference electrodes include the standard hydrogen electrode, which defines zero potential, and silver/silver chloride electrodes. Reference electrodes are used along with indicator or working electrodes in electrochemical cells to measure the potential difference between the electrodes, which depends on the analyte concentration.
This document discusses oxidation-reduction (redox) reactions. It defines oxidation as the loss of electrons and reduction as the gain of electrons. Redox reactions always involve a transfer of electrons between reactants. The key principles are:
1. Oxidation and reduction always occur together in a redox reaction.
2. The total number of electrons lost must equal the total number of electrons gained to satisfy the conservation of charge.
3. Redox titrations can be used to determine the concentration of an unknown substance and rely on a redox reaction between a titrant and analyte with an indicator or potentiometer used to find the endpoint.
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.
This document discusses the principles and methods of voltammetry and polarography. Some key points:
- Voltammetry measures the current-potential curve during electrolysis using a small amount of sample. Polarography uses a dropping mercury electrode as the working electrode.
- In polarographic analysis, a polarized working electrode and depolarized reference electrode are used. No stirring is used. Only a small amount of analyte undergoes electrolysis.
- The limiting diffusion current is proportional to analyte concentration and can be used for quantitative analysis. The half-wave potential is used for qualitative analysis.
- Factors like temperature, supporting electrolyte composition, and mercury electrode potential affect the limiting diffusion current.
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.
A ppt compiled by Yaseen Aziz Wani pursuing M.Sc Chemistry at University of Kashmir, J&K, India and Naveed Bashir Dar, a student of electrical engg. at NIT Srinagar.
Warm regards to Munnazir Bashir also for providing us with refreshing tea while we were compiling ppt.
This document discusses the key components of a UV-Visible spectrophotometer. It describes the light sources used, including tungsten filament lamps, deuterium lamps, and mercury arc lamps. It also covers the collimating system of lenses and mirrors that direct the light beam, as well as wavelength selectors like filters and monochromators that isolate specific wavelengths. Common types of monochromators like prism and diffraction grating designs are outlined. The document provides details on how these components work together to generate spectra that can be used to analyze samples.
This document discusses the Woodward-Fieser rules for predicting the wavelength of maximum absorption (λmax) of organic compounds based on their molecular structure. It introduces the basic terminology and presents the parent values and incremental contributions for calculating λmax for different functional groups in conjugated dienes, aromatics, α,β-unsaturated carbonyls, and compounds with more than four conjugated double bonds. Examples are provided to demonstrate the application of the rules for each class of compounds. The document is intended as an introduction to the Woodward-Fieser rules and their use in predicting UV-vis absorption spectra based on molecular structure.
First part of Statistical Thermodynamics includes: Introduction, Ensembles, Types of Ensembles, Thermodynamic Probability, Boltzmann Distribution, Lagrange's Undetermined Multipliers, Partition Function, Types of Partition Functions, Thermodynamic Properties in terms of partition Function, Heat Capacity, Heat Capacity of Monoatomic Solids, Dulong-Petit law, Einstein Model for solids, 3rd Law and Residual Entropy
Coherent Anti Stokes Raman Spectroscopy SPCGC AJMER
This document provides an overview of coherent anti-Stokes Raman spectroscopy (CARS). It begins with an introduction to CARS and its history. The theoretical background of CARS is then explained, including the basics of Rayleigh and Raman scattering. The document outlines the CARS process, advantages and limitations of CARS, and applications. It concludes with a summary of the key points regarding CARS spectroscopy.
This document provides procedures for preparing several transition metal complexes. It describes preparing hexaamminecobalt(III)chloride from cobaltous chloride hexahydrate and ammonium chloride. It also describes preparing hexaamminenickel(II)chloride from nickel chloride hexahydrate and aqueous ammonia, as well as potassium tris(oxalato)ferrate(III) trihydrate from ferrous ammonium sulfate and oxalic acid. The document gives the name, structure, properties and theoretical yield calculations for each complex prepared.
1) The document discusses volumetric analysis, which is a quantitative chemical analysis method that involves titration. It is defined as determining the concentration of an unknown solution by titrating a known volume of it with a solution of known concentration.
2) Key terms in volumetric analysis are discussed, including titration, titrant, equivalence point, indicator, end point, and titration error.
3) Requirements for volumetric analysis are that the reaction must be complete, stoichiometric, relatively fast, and have a detectable physical or chemical change at the equivalence point that can be identified using an indicator.
This document provides an overview of conductometry and its applications. It discusses Ohm's law and how conductivity is measured using electrodes, standard solutions, and a conductivity cell. Factors that affect conductivity include ion size, temperature, charge, and number. Conductometric titrations can be used to determine endpoints and are advantageous because no indicator is needed. Types of titrations discussed include acid-base, precipitation, replacement, redox, and complexometric. Recent applications include use in refineries, estimating polyelectrolytes, and biotechnology/environmental monitoring.
1. Photochemistry is the study of chemical reactions caused by the absorption of light. It involves photochemical reactions, which require light for initiation, as well as photophysical processes during the de-excitation of excited molecules.
2. Key concepts in photochemistry include Grotthuss-Draper law, Lambert's law, Beer's law, and Stark-Einstein law of photochemical equivalence. Quantum yield determines the efficiency of photochemical reactions.
3. Photochemistry examines differences between photochemical and thermal reactions. It also explores photochemical processes like fluorescence, phosphorescence, internal conversion, and intersystem crossing depicted in Jablonski diagrams.
The document summarizes the pH glass electrode, which is used to measure pH through the detection of hydrogen ion activity. It functions as a fast responding, hydrogen ion selective electrode. The electrode contains a lithium silicate glass membrane that forms a hydrated gel layer, allowing only hydrogen ions to penetrate and alter the electrochemical potential between the glass and reference electrode. It is able to measure pH based on the Nernst equation, with the potential changing approximately 60mV for every unit change in pH.
Nuclear Quadrupole Resonance Spectroscopy (NQR) is a chemical analysis technique that detects nuclear energy level transitions in the absence of a magnetic field through the absorption of radio frequency radiation. NQR is applicable to solids due to the quadrupole moment averaging to zero in liquids and gases. The interaction between a nucleus's quadrupole moment and the electric field gradient of its surroundings results in quantized energy levels. Transitions between these levels are detected as NQR spectra and provide information about electronic structure, hybridization, and charge distribution. NQR finds applications in studying charge transfer complexes, detecting crystal imperfections, and locating land mines.
This document discusses statistical thermodynamics and the partition function. It introduces the concept of microscopic configurations and their weights. The Boltzmann distribution relates the probability of a configuration to its weight, which depends on the energy levels and temperature. The partition function allows calculating thermodynamic properties like internal energy, entropy, and heat capacity from knowledge of the energy levels and degeneracies alone. It provides a statistical mechanical approach to thermodynamics.
pH and Potentiometry, Potentiometric titrations, Electrodes used in Potentiometry, Standard Hydrougen electrode, calamel electrode, silver silver chloride electrode, glass electrode
This document summarizes voltammetry, an electrochemical method that uses a three-electrode system to obtain information about analytes. A voltage ramp is applied to the working electrode to reduce ions, while current is measured. Common types of voltammetry include cyclic, square wave, differential pulse, and stripping voltammetry. The working electrode potential is varied over time, while the reference electrode potential remains constant. Voltammetry can be used to determine metal ion concentrations, for wastewater analysis, and in various other applications due to its low detection limits and ability to handle high salt concentrations.
This document provides information on potentiometry and potentiometric titration. It discusses the basic principles of potentiometry including electrode potentials and how a potential difference is established between an electrode and solution. It describes the instrumentation used including reference electrodes like calomel and silver-silver chloride electrodes and indicator electrodes like metal, glass membrane, and quinhydrone electrodes. It also discusses different types of potentiometric titrations and provides examples of applications for potentiometry in various industries.
This document summarizes amperometric titration, a technique where the current is measured during titration using a constant applied potential. It discusses the principles, apparatus, types (including titration of reducible vs. non-reducible ions and redox titrations), advantages, and applications of amperometric titration. The rotating platinum microelectrode apparatus allows a potential to be applied while measuring the current. Amperometric titration can be used to quantify reducible and non-reducible ions and is useful for dilute solutions.
Conductometric analysis measures the electrical conductivity of solutions to determine analyte concentration. It works by measuring how easily ions move through the solution when a current is applied. There are several types of conductometric titrations including acid-base, redox, and complexometric titrations. Conductometric titrations can determine the endpoint graphically without needing indicators and work well for colored, weak, or turbid solutions. The conductivity is measured using a conductometer with conductivity cells and platinum electrodes to apply a current and measure the solution's resistance.
Potentiometry is a method of analysis that determines the concentration of an ion or substance by measuring the potential developed at a sensitive indicator electrode immersed in the solution. There are two main types of indicator electrodes: metallic electrodes where redox reactions occur on the surface, and membrane electrodes where charge exchange occurs across a selective surface. Reference electrodes such as silver/silver chloride are used along with indicator electrodes to complete the circuit and allow measurement of potential. Potentiometry can be used for direct concentration measurements or titration applications such as acid-base, precipitation, complexation, and redox reactions.
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.
Electroanalytical methods provide several advantages for quantitative analytical chemistry. They involve measuring the electrical properties of analyte solutions in electrochemical cells. Some key points:
- Electroanalytical methods allow easy automation through electrical signal measurements. They can also determine low analyte concentrations without difficulty.
- Electrochemical processes involve the transfer of electrons between substances during redox reactions. This occurs at the interface between electrodes and solutions in electrochemical cells.
- Advantages include low cost compared to spectroscopy and the ability to easily automate measurements and detect low analyte concentrations through electrical signals.
A ppt compiled by Yaseen Aziz Wani pursuing M.Sc Chemistry at University of Kashmir, J&K, India and Naveed Bashir Dar, a student of electrical engg. at NIT Srinagar.
Warm regards to Munnazir Bashir also for providing us with refreshing tea while we were compiling ppt.
This document discusses the key components of a UV-Visible spectrophotometer. It describes the light sources used, including tungsten filament lamps, deuterium lamps, and mercury arc lamps. It also covers the collimating system of lenses and mirrors that direct the light beam, as well as wavelength selectors like filters and monochromators that isolate specific wavelengths. Common types of monochromators like prism and diffraction grating designs are outlined. The document provides details on how these components work together to generate spectra that can be used to analyze samples.
This document discusses the Woodward-Fieser rules for predicting the wavelength of maximum absorption (λmax) of organic compounds based on their molecular structure. It introduces the basic terminology and presents the parent values and incremental contributions for calculating λmax for different functional groups in conjugated dienes, aromatics, α,β-unsaturated carbonyls, and compounds with more than four conjugated double bonds. Examples are provided to demonstrate the application of the rules for each class of compounds. The document is intended as an introduction to the Woodward-Fieser rules and their use in predicting UV-vis absorption spectra based on molecular structure.
First part of Statistical Thermodynamics includes: Introduction, Ensembles, Types of Ensembles, Thermodynamic Probability, Boltzmann Distribution, Lagrange's Undetermined Multipliers, Partition Function, Types of Partition Functions, Thermodynamic Properties in terms of partition Function, Heat Capacity, Heat Capacity of Monoatomic Solids, Dulong-Petit law, Einstein Model for solids, 3rd Law and Residual Entropy
Coherent Anti Stokes Raman Spectroscopy SPCGC AJMER
This document provides an overview of coherent anti-Stokes Raman spectroscopy (CARS). It begins with an introduction to CARS and its history. The theoretical background of CARS is then explained, including the basics of Rayleigh and Raman scattering. The document outlines the CARS process, advantages and limitations of CARS, and applications. It concludes with a summary of the key points regarding CARS spectroscopy.
This document provides procedures for preparing several transition metal complexes. It describes preparing hexaamminecobalt(III)chloride from cobaltous chloride hexahydrate and ammonium chloride. It also describes preparing hexaamminenickel(II)chloride from nickel chloride hexahydrate and aqueous ammonia, as well as potassium tris(oxalato)ferrate(III) trihydrate from ferrous ammonium sulfate and oxalic acid. The document gives the name, structure, properties and theoretical yield calculations for each complex prepared.
1) The document discusses volumetric analysis, which is a quantitative chemical analysis method that involves titration. It is defined as determining the concentration of an unknown solution by titrating a known volume of it with a solution of known concentration.
2) Key terms in volumetric analysis are discussed, including titration, titrant, equivalence point, indicator, end point, and titration error.
3) Requirements for volumetric analysis are that the reaction must be complete, stoichiometric, relatively fast, and have a detectable physical or chemical change at the equivalence point that can be identified using an indicator.
This document provides an overview of conductometry and its applications. It discusses Ohm's law and how conductivity is measured using electrodes, standard solutions, and a conductivity cell. Factors that affect conductivity include ion size, temperature, charge, and number. Conductometric titrations can be used to determine endpoints and are advantageous because no indicator is needed. Types of titrations discussed include acid-base, precipitation, replacement, redox, and complexometric. Recent applications include use in refineries, estimating polyelectrolytes, and biotechnology/environmental monitoring.
1. Photochemistry is the study of chemical reactions caused by the absorption of light. It involves photochemical reactions, which require light for initiation, as well as photophysical processes during the de-excitation of excited molecules.
2. Key concepts in photochemistry include Grotthuss-Draper law, Lambert's law, Beer's law, and Stark-Einstein law of photochemical equivalence. Quantum yield determines the efficiency of photochemical reactions.
3. Photochemistry examines differences between photochemical and thermal reactions. It also explores photochemical processes like fluorescence, phosphorescence, internal conversion, and intersystem crossing depicted in Jablonski diagrams.
The document summarizes the pH glass electrode, which is used to measure pH through the detection of hydrogen ion activity. It functions as a fast responding, hydrogen ion selective electrode. The electrode contains a lithium silicate glass membrane that forms a hydrated gel layer, allowing only hydrogen ions to penetrate and alter the electrochemical potential between the glass and reference electrode. It is able to measure pH based on the Nernst equation, with the potential changing approximately 60mV for every unit change in pH.
Nuclear Quadrupole Resonance Spectroscopy (NQR) is a chemical analysis technique that detects nuclear energy level transitions in the absence of a magnetic field through the absorption of radio frequency radiation. NQR is applicable to solids due to the quadrupole moment averaging to zero in liquids and gases. The interaction between a nucleus's quadrupole moment and the electric field gradient of its surroundings results in quantized energy levels. Transitions between these levels are detected as NQR spectra and provide information about electronic structure, hybridization, and charge distribution. NQR finds applications in studying charge transfer complexes, detecting crystal imperfections, and locating land mines.
This document discusses statistical thermodynamics and the partition function. It introduces the concept of microscopic configurations and their weights. The Boltzmann distribution relates the probability of a configuration to its weight, which depends on the energy levels and temperature. The partition function allows calculating thermodynamic properties like internal energy, entropy, and heat capacity from knowledge of the energy levels and degeneracies alone. It provides a statistical mechanical approach to thermodynamics.
pH and Potentiometry, Potentiometric titrations, Electrodes used in Potentiometry, Standard Hydrougen electrode, calamel electrode, silver silver chloride electrode, glass electrode
This document summarizes voltammetry, an electrochemical method that uses a three-electrode system to obtain information about analytes. A voltage ramp is applied to the working electrode to reduce ions, while current is measured. Common types of voltammetry include cyclic, square wave, differential pulse, and stripping voltammetry. The working electrode potential is varied over time, while the reference electrode potential remains constant. Voltammetry can be used to determine metal ion concentrations, for wastewater analysis, and in various other applications due to its low detection limits and ability to handle high salt concentrations.
This document provides information on potentiometry and potentiometric titration. It discusses the basic principles of potentiometry including electrode potentials and how a potential difference is established between an electrode and solution. It describes the instrumentation used including reference electrodes like calomel and silver-silver chloride electrodes and indicator electrodes like metal, glass membrane, and quinhydrone electrodes. It also discusses different types of potentiometric titrations and provides examples of applications for potentiometry in various industries.
This document summarizes amperometric titration, a technique where the current is measured during titration using a constant applied potential. It discusses the principles, apparatus, types (including titration of reducible vs. non-reducible ions and redox titrations), advantages, and applications of amperometric titration. The rotating platinum microelectrode apparatus allows a potential to be applied while measuring the current. Amperometric titration can be used to quantify reducible and non-reducible ions and is useful for dilute solutions.
Conductometric analysis measures the electrical conductivity of solutions to determine analyte concentration. It works by measuring how easily ions move through the solution when a current is applied. There are several types of conductometric titrations including acid-base, redox, and complexometric titrations. Conductometric titrations can determine the endpoint graphically without needing indicators and work well for colored, weak, or turbid solutions. The conductivity is measured using a conductometer with conductivity cells and platinum electrodes to apply a current and measure the solution's resistance.
Potentiometry is a method of analysis that determines the concentration of an ion or substance by measuring the potential developed at a sensitive indicator electrode immersed in the solution. There are two main types of indicator electrodes: metallic electrodes where redox reactions occur on the surface, and membrane electrodes where charge exchange occurs across a selective surface. Reference electrodes such as silver/silver chloride are used along with indicator electrodes to complete the circuit and allow measurement of potential. Potentiometry can be used for direct concentration measurements or titration applications such as acid-base, precipitation, complexation, and redox reactions.
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.
Electroanalytical methods provide several advantages for quantitative analytical chemistry. They involve measuring the electrical properties of analyte solutions in electrochemical cells. Some key points:
- Electroanalytical methods allow easy automation through electrical signal measurements. They can also determine low analyte concentrations without difficulty.
- Electrochemical processes involve the transfer of electrons between substances during redox reactions. This occurs at the interface between electrodes and solutions in electrochemical cells.
- Advantages include low cost compared to spectroscopy and the ability to easily automate measurements and detect low analyte concentrations through electrical signals.
The document discusses electrochemistry and Daniel cells. It provides details on:
- How Daniel cells work by converting chemical energy from a redox reaction of zinc and copper into electrical energy.
- The components of a Daniel cell including zinc and copper electrodes, zinc sulfate and copper sulfate solutions, and a salt bridge to maintain electrical neutrality.
- How the cell produces a voltage through the oxidation of zinc and reduction of copper ions.
- How the voltage depends on the concentration of ions, as described by the Nernst equation.
This document provides an overview of the key concepts in electrochemistry including oxidation-reduction reactions, galvanic cells, standard reduction potentials, the Nernst equation, electrolysis, batteries, corrosion, and commercial electrolytic processes. It defines important terms, describes experimental set ups and calculations for electrochemical cells, and summarizes fundamental electrochemical principles and laws such as Faraday's laws of electrolysis.
This document provides an overview of electrochemistry concepts including:
- Types of electrochemical processes including reversible and irreversible processes.
- Oxidation-reduction reactions and how they involve oxidation and reduction half-reactions.
- Galvanic/voltaic cells and how they generate electricity from spontaneous redox reactions.
- Components of electrochemical cells including electrodes, salt bridges, and how they allow indirect redox reactions.
- Standard electrode potentials and how they are used to determine if a reaction is spontaneous.
- The Nernst equation and how it describes the dependence of electrode potential on ion concentration.
Module 2_S7 and S8_Electrochemical Cells.pptxAdittyaSenGupta
An electrochemical cell consists of two electrodes separated by an electrolyte. There are two types: galvanic cells and electrolytic cells. A galvanic cell converts the chemical energy of a spontaneous redox reaction directly into electrical energy. The Nernst equation relates the cell potential (E) of a galvanic cell to the standard potential (E0), temperature, and reaction quotient through the concentrations of reactants and products. It allows calculation of cell potential under non-standard conditions.
Potentiometry involves measuring the potential (voltage) between an indicator electrode and a reference electrode immersed in a solution. The potential measurement provides information about the concentration of an analyte in the solution. Common reference electrodes include the saturated calomel electrode (SCE) and silver-silver chloride electrode, which maintain a constant potential. pH electrodes function as indicator electrodes, with their potential directly proportional to the pH of the solution. The potential measurement is made against the reference electrode using a pH meter, which can be calibrated using buffer solutions.
This document provides an overview of key concepts in electrochemistry, including:
- Galvanic cells use spontaneous chemical reactions to generate electrical energy, while electrolytic cells use an applied voltage to drive nonspontaneous reactions.
- Cell potentials and the Nernst equation relate the standard cell potential to non-standard state potentials based on reaction quotients.
- Faraday's law of electrolysis states that the amount of product formed is proportional to the quantity of electricity passed, as measured by coulombs of charge.
- Standard reduction potentials and Gibbs free energy can be used to determine cell potentials and predict spontaneity of redox reactions.
This document provides an overview of key concepts in electrochemistry, including:
- Galvanic cells use spontaneous chemical reactions to generate electrical energy, while electrolytic cells use an applied voltage to drive nonspontaneous reactions.
- Oxidation occurs at the anode and reduction at the cathode. Standard cell potential and Faraday's law relate the electrical work done to chemical reactions.
- Faraday's law states that the amount of product formed during electrolysis is directly proportional to the charge passed, allowing calculations of moles reacted given current and time.
- Standard cell potential and the Nernst equation describe how cell potential varies with reaction conditions versus under standard states.
Electrochemistry is the study of electron movement in an oxidation or reduction reaction at a polarized electrode surface. Each analyte is oxidized or reduced at a specific potential and the current measured is proportional to concentration. This technique is a powerful methodology towards bioanalysis.
https://www.sciencedirect.com › ele...
Electrochemistry - an overv
This document discusses electrochemistry and the Nernst equation. It begins by defining electrochemistry and describing the basic components of an electrochemical cell including electrodes, salt bridge, and cell potential. It then explains the Nernst equation and how it can be used to calculate cell potential based on concentrations. Different types of electrodes are described such as metal-metal ion, gas, redox, and ion selective electrodes. Applications of the Nernst equation include calculating electrode potentials, equilibrium constants, and determining pH. Finally, Frost diagrams are introduced as a graphical way to represent redox potentials and stability.
This document discusses electrochemistry and electrochemical cells. It defines electrochemistry as the study of chemical reactions that produce electricity or use electricity to cause reactions. There are two types of electrochemical cells: galvanic cells that convert chemical energy to electrical energy, and electrolytic cells that use electrical energy to drive non-spontaneous reactions. Examples of galvanic cells include Daniell cells and concentration cells. The document explains concepts like standard electrode potentials, the electrochemical series, and how to represent cell diagrams according to IUPAC recommendations. It also discusses the functions of salt bridges and how junction potentials can affect cell potentials.
This document provides an overview of electrochemistry and discusses several topics including:
- Electrochemistry involves the interconversion of electrical and chemical energy. Electrolytic cells convert electrical to chemical, while electrochemical cells do the reverse.
- Electrodes, the Nernst equation, and the electrochemical series are introduced. Common reference electrodes like the standard hydrogen electrode and calomel electrode are also described.
- Determination of pH using hydrogen, glass, and quinhydrone electrodes is explained through representative half-cell reactions and the Nernst equation. Advantages and disadvantages of the different indicator electrodes are also summarized.
Electrochemistry is the study of chemical reactions involving the transfer of electrons. Oxidation and reduction reactions occur in electrochemical cells. Daniel cell is an example of a galvanic cell that converts chemical energy to electrical energy. It consists of zinc and copper half cells separated by a salt bridge. The cell potential depends on the standard electrode potentials of the half reactions and can be calculated using Nernst's equation. Equilibrium constants can also be determined from standard cell potentials using thermodynamic relationships.
This document discusses electrochemistry and provides details about electrochemical cells. It contains the following key points:
1. Electrochemistry is the study of production of electricity from chemical reactions and use of electrical energy to drive non-spontaneous reactions.
2. An electrochemical cell converts chemical energy to electrical energy (galvanic/voltaic cell) or electrical energy to chemical energy (electrolytic cell).
3. A Daniell cell is a voltaic cell that generates a voltage of 1.1V from the redox reaction of zinc and copper. Measurement of electrode potentials and the Nernst equation are also discussed.
Electrochemistry deals with chemical reactions caused by electric currents or electric currents produced by chemical reactions. Galvanic cells convert chemical energy to electrical energy through redox reactions. Reversible cells like Daniel cells can undergo reactions in both directions while irreversible cells like zinc-silver cells cannot. Protective metal coatings through electroplating or electroless plating prevent corrosion by depositing a noble metal layer on a substrate.
Electrochemistry class 12 ( a continuation of redox reaction of grade 11)ritik
Electrochemistry involves the study of chemical reactions that produce electricity and chemical reactions produced by electricity. A galvanic (voltaic) cell converts the chemical energy of a spontaneous redox reaction into electrical energy. Daniell's cell uses the redox reaction of zinc oxidizing copper ions to produce a cell potential of 1.1 V. An electrolytic cell uses an applied voltage to drive a nonspontaneous redox reaction in the opposite direction of the natural reaction in a galvanic cell. Standard reduction potentials allow prediction of the tendency of half-reactions to occur and their oxidizing or reducing power.
This document provides an overview of electrochemistry and discusses several key concepts:
- Electrochemistry involves using chemical reactions to produce electricity or using electricity to drive non-spontaneous reactions.
- Oxidation and reduction reactions occur at electrodes in electrochemical cells. The standard electrode potential table allows determination of reaction spontaneity.
- Daniell cells convert the chemical energy of a redox reaction into electrical energy. The cell potential is equal to the difference between the standard potentials of the cathode and anode half-reactions.
1. The document describes an experiment to test the validity of the Nernst equation by measuring the voltage of electrochemical cells containing varying concentrations of zinc or magnesium ions.
2. Results show cell voltage decreases with decreasing log of the concentration of zinc ions, following the linear relationship predicted by the Nernst equation.
3. A magnesium-copper cell is also constructed, producing enough voltage to power a small LED, demonstrating a spontaneous redox reaction and energy conversion.
Electrochemistry is the study of chemical reactions that produce electricity and electrical energy's ability to cause non-spontaneous reactions. There are two types of electrochemical cells: galvanic cells that convert chemical energy to electrical energy, and electrolytic cells that use electrical energy to drive non-spontaneous reactions. Galvanic cells contain a spontaneous redox reaction like in Daniel cells where zinc oxidizes and copper reduces. Electrolytic cells use an external voltage to force nonspontaneous redox reactions. Standard electrode potentials allow prediction of reaction spontaneity based on the cell potential relative to the standard hydrogen electrode.
ORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECTORGANIZATION CHART OF THE PROJECT
Construction equipment- classification, factors affecting its selection.pptxShivamKumar423966
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21/08/2015 · Department of Civil Technology Written By: Ahmed Zakaria Page 11 Hosting Company: Fig 2: Al haramain Company headquarter Company address: Al Haramain Company for Commerce and Contracting Building Al Nahda Area Jeddah 2233 Saudi Arabia +966 2 694 2000 ahc@haramain.com.sa. 12.
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It has been operational in Pakistan since 1989. Toyota is a one of a kind Japanese multinational automotive manufacturer. As of September 2018, it was the sixth largest company in the world in terms of revenue. The economic conditions however have not been very favorable for the automotive industry.
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#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
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- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
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- Create S3 bucket.
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- Exploiting IAM PassRole Misconfiguration
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- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
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- Allow user to pass IAM role to EC2.
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- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
6. Representation of galvanic cell.
• Anode Representation:
Zn│Zn2+
(1M) or Zn ; Zn2+
(1M)
Zn │ ZnSO4 (1M) or Zn ; ZnSO4 (1M)
• Cathode Representation:
Cu2+
(1M) │ Cu or Cu2+
(1M) ;Cu
Cu2+
(1M) ; Cu or CuSO4(1M) │ Cu
• Cell Representation:
Zn │ ZnSO4 (1M)║ CuSO4(1M) │Cu
7. Anode:
• Electrode at which oxidation occurs
• is where electrons are produced
• has a negative sign
Cathode:
* Electrode at which reduction occurs
• is where electrons are consumed
• has a positive sign
Oxdn. Is Losing Electrons, Rdn. Is Gaining Electrons
Anode vs Cathode in Galvanic cell
10. Comparison between Galvanic and
Electrolytic Cell
Galvanic Cell
• Cell reaction is spontaneous
• Converts Chemical Energy to
Electrical Energy
• Anode is negative terminal and
cathode is positive terminal
• Have two electrodes and two
electrolytes
• Used as portable source of
electric energy.
• Salt bridge is used
• Eg: Daniel Cell
Electrolytic Cell
• Cell reaction is non spontaneous
• Converts Electrical Energy into
Chemical Energy
• Anode is positive terminal and
cathode is negative terminal
• Have two electrodes and single
electrolyte
• Used in Electrolysis apparatus.
• Salt bridge is not used
• Eg : Electroplating.
11. Comparison…….contd..
•Similarities:
•Involves oxidation at anode & reduction at cathode
• oxidation & reduction in the separate regions
•Electrons flow from anode to cathode in the external
circuit
•Reactions occur on electrode surface only
14. Liquid Junction Potential (LJP)
• Difference between the
electric potentials
developed in the two
solutions across their
interface .
• Ej = Ø soln, R − Ø soln,L
Eg: Contact between:
Two different electrolytes
(ZnSO4/ CuSO4).
Same electrolytes of
different concentrations.
With Porous disc
16. Salt Bridge - Elimination of LJP
A device that permits electrical contact between two solutions,
while preventing direct reaction between the reactants/mixing.
Cell: Zn/Zn2+(0.01M) // Cu2+(0.1M)/Cu
17. It maintains electrical neutrality in the two half cells
It provides electrical contact between the two electrolyte solutions
of a cell
It minimizes LJP in galvanic cells containing two dissimilar
solutions in contact
Functions of SB
salts used in salt
bridge: potassium nitrate,
potassium chloride, ammonium
nitrate etc.
18. Origin of single electrode potential
Zinc ions moves into
solution leaving
behind electrons
making it electron rich
Copper ions gets deposited as
copper leaving behind free
negatively charged sulfate ions in
solution makes the electrode
electron poor
19. The rate of the reaction depends on the
• nature of metal
• temperature
• concentration of the metal ions in the solution
Helmholtz electrical double layer
20. Measurement of electrode
potential
• It is impossible to determine the absolute half cell potential.
• We can only measure the difference in potential between two
electrodes potentiometrically, by combining them to form a
complete cell.
Platinum
SHE
https://www.google.com/search?q=measuring+single+electrode+potential+of+zinc+electrode+w
hen+copuled+with+SHE&rlz=1C1CHBF_enIN922IN922&source=lnms&tbm=isch&sa=X&ved=2ahU
KEwjb-rD-5MDsAhVD4jgGHQX8AwwQ_AUoAXoECBUQAw&biw=1366&bih=625#imgrc=sQH-
GZEvHbrCjM
23. Standard electrode potential: E0 is the electrode potential
when electrode is in contact with a solution of unit concentration at
298 K involving pure solids and liquids
24. Nernst Equation
An expression of a quantitative relationship between electrode
potential/cell potential and concentration of the electrolyte
species in an electro-chemical reaction
Mn+
aq) + ne- M(s)
Vant Hoff reaction isotherm: R = 8.314J/mol/K T in kelvin
F = 96500 C
K
ln
RT
o
G
G
]
[M
[M]
ln
RT
G
G n
o
]
[M
[M]
ln
RT
nFE
nFE n
o
]
[M
1
ln
nF
RT
E
E n
o
]
[M
1
log
nF
RT
2.303
E
E n
o
K,
T
At 298
]
[M
1
log
n
0.0592
E
E n
o
]
[M
log
n
0.0592
E
E n
o
25. Nernst Equation
.
From Nernst equation,
If concentration of solution (Mn+) and temperature is increased, the
electrode potential increases and vice versa.
anode
at
species
of
Conc
Cathode
at
species
of
Conc
log
nF
RT
303
.
2
E
E 0
cell
cell
For Daniel cell
2
2
A
o
C
0
cell
zn
Cu
log
nF
RT
303
.
2
E
-
E
E
26. Significance of the Nernst equation
• To calculate the potential of a cell that operates under non-standard
conditions.
• To measure the equilibrium constant for a reaction, when the overall
cell potential for the reaction is zero
At equilibrium the overall cell potential for the reaction is zero. i.e. E=0
Nernst equation,
E=E° - (RT/nF)lnKc
0 = Eo - RT/nF lnKc
Eo = RT/nF lnKc
RTlnKc = nFE°
Kc = e nFE° / RT
27. Emf of a cell
The difference of potential, which causes a current to flow from
the electrode of higher potential to one of lower potential.
Ecell = Ecathode- Eanode
ECell 3 factors:
*The nature/composition of the electrodes
*Temperature E α T
*Conc. of the electrolyte solns E α C.
Ecell is always +ve
ΔG = - nFE
28. Standard emf of a cell(Eo
cell) is defined as the emf of a cell when the
reactants & products of the cell reaction are at unit concentration or
unit activity, at 298 K and at 1 atmospheric pressure.
The emf cannot be measured accurately using ordinary voltmeter
• part of the cell current is drawn to deflect the needle
• part of the emf is used to overcome the internal resistance of the
cell
Measured emf < actual emf of cell
29. The potentiometric measurement of emf of a cell:
Poggendorff’s compensation method
AB- Potentiometric wire
ES- Standard cell
Ex- unknown cell
G- Galvanometer
J- Sliding contact.
C-Rh – adjustable resistance
S- Storage battery
The emf of the cell Ex is
proportional to the length AD
Ex α AD
The emf of the standard cell Es is
proportional to the length AD1
Es α AD1
Ex ═ AD
Es AD1
Ex = AD x Es
AD1
+ -
G
J
S
C
Rh
B
A
Ex
Es
D D’
31. Energetics of Cell Reactions
• Net electrical work performed by the cell reaction of a galvanic cell:
W = QE ------ (1)
Q is the quantity of electrical charge in coulombs produced by the reaction and E is
the emf of the cell in volts
Charge on 1mole of electrons = F Coulombs (96,500 )
When ‘n’ moles of electrons are involved in the cell reaction,
the total charge on ‘n’ moles of electrons = nF coulombs
Q = nF
Substituting for Q , W = nFE
The cell does net work at the expense of the decrease in free energy change (ΔG)
accompanying the cell reaction
i.e., Net electrical work = Decrease in free energy
ΔG = - nFE
33. Gas electrode.
• It consists of gas bubbling over an inert metal wire or foil
immersed in a solution containing ions of the gas.
• Standard hydrogen electrode is the primary reference electrode,
whose electrode potential at all temperature is taken as zero
arbitrarily.
Platinum
34. • Representation: Pt,H2(g)/ H+
• Electrode reaction: H+ + e- 1/2 H2(g)
The electrode reaction is reversible as it can undergo either
oxidation or reduction depending on the other half cell.
• If the concentration of the H+ ions is 1M, pressure of H2 is 1atm
at 298K it is called as standard hydrogen electrode (SHE).
Limitations
Construction and working is difficult.
Pt is susceptible for poisoning.
Cannot be used in the presence of oxidizing agents.
35. Applications
• Primary reference electrode: To determine electrode potential of
other unknown electrodes
• Electrode potential of Hydrogen Electrode is given as follows:
• H+ + e- 1/2 H2(g)
• E = Eo - 2.303 RT/nF log [H2]1/2/[H+]
E = 0 - 0.0591 log 1/[H+]
E = - 0.0591pH
To determine the pH of a solution. Cell Scheme: Pt,H2,H+
(x)// SHE
• The emf of the cell is determined.
• E (cell) = E (C) – E(A)
E (cell) = 0 – (- 0.0592 pH)
E (cell) = 0.0592 pH
pH = E(cell)/ 0.0592
36. • Consists of a tube, in the
bottom of which is a layer
of mercury, over which is
placed a paste of mercury
and mercurous chloride.
• Remaining portion of the
cell is filled with a solution
of normal/decinormal/
saturated solution of KCl.
• A platinum wire sealed at its
end fixed into the main tube
dipping into the mercury
layer for electrical contact.
Calomel electrode
37. • Representation: Hg; Hg2Cl2 / KCl
2Hg → Hg2
2+ + 2e- Hg2
2+ + 2Cl- → Hg2Cl2
As anode: 2Hg + 2Cl- → Hg2Cl2 + 2e-
As Cathode: Hg2Cl2 + 2e- → 2Hg + 2 Cl-
E= Eo - 0.0591 log [Cl-]2 at 298 K
2
Nernst equation E= Eo - 0.0591 log [Cl-] at 298 K
Its electrode potential depends on the concentration of KCl.
Conc. of Cl- Electrode potential
0.1M 0.3335 V
1.0 M 0.2810 V
Saturated 0.2422/2444 V
Calomel electrode
[Reactant]
[product]
log
n
0.0592
E
E o
38. To determine the EMF of a cell and pH of a solution.
Pt|H2|H+
(X) ||KCl|Hg2Cl2|Hg
Ecell= 0.2422-(- 0.0592pH)
pH = (Ecell – 0.2422) / 0.0592
Calomel electrode
39. Advantages
• It is very simple to construct.
• It can be used for a long time without much attention.
• Electrode potential is stable over a long period.
• It has low temperature coefficient of emf.
• It is less prone to contamination.
Disadvantages
• Calomel electrodes should not be used above 50oC .
• Calomel electrode should be used with proper precaution as
mercury compounds are toxic.
Calomel electrode
40. 40
The emf of a cell consisting of a hydrogen and the
normal calomel is 0.664 V at 25 C. Calculate the pH
of the solution containing the hydrogen electrode.
Ecell= Ecal (normal) –( −0.0591pH)
0.664 = 0.2810+0.0591 pH
0.383=0.0591 pH
pH= 6.48
41. Ion Selective Electrode
The electrode which is sensitive to a specific ion
present in an electrolyte whose potential
depends upon the activity of specific ion in the
electrolyte is called ion selective electrode.
The magnitude of potential of this electrode is an
indicator of the activity of the specific ion in the
electrolyte. Example for this type of electrode is
glass electrode.
42. The electrode consists of a thin glass membrane
(about 50 micrometer thick), sealed onto one end
of a heavy–walled glass tube.
A special variety of glass (corning 0l5 glass with
approximate composition 20% Na2O, 6% CaO &
72% SiO2) is used
It has low melting point and high electrical
resistance.
The glass bulb is filled with a solution of constant
pH (0.1 M HCl).
42
43. A silicate glass used for membranes consists of an
infinite 3D- network of SiO4
4- groups
There are sufficient cations to balance the negative
charge of the silicate groups within the interstices
of this structure.
Singly charged cations such as sodium and lithium
are mobile in the lattice and are responsible for
electrical conduction within the membrane.
The glass is a partially hydrated aluminosilicate
containing sodium or calcium ions.
43
44. The silica glass structure is shaped in such a way
that it allows Na+ ions some mobility. The metal
cations in the hydrated gel diffuse out of the
glass and into the solution while H+ from
solution can diffuse into the hydrated gel.
44
45. Silver/silver chloride reference electrode which
is connected to one of the terminals of a
potential measuring device.
Note that internal reference electrode is a part
of the glass electrode and it is not the pH
sensing element.
Only the potential that occurs between the
outer surface of the glass bulb and the test
solution responds to pH changes.
48. Schematic diagram of the
structure of glass, which consist of an irregular
network of SiO4 tetrahedra connected through
Oxygen atoms.
Cations are coordinated to the oxygen atoms.
49.
50. Electrode Potential of glass electrode.
The overall potential of the glass electrode is given by:
Eg = Eb + Eref. + Easy.
It has three components:
The boundary potential Eb,
Internal reference electrode potential Eref.
Asymmetric potential Easy
51. • Eb = E1 – E2
= (RT/nF) ln C1 – (RT/nF) ln C2
= L + (RT/nF) ln C1
Eb depends upon [H+]
Eg = Eb + EAg/AgCl + Easy
= L + (RT/nF) ln C1 + EAg/AgCl + Easy.
= Eo
g + (RT/nF) ln C1
= Eo
g + 0.0592 log [H+]
Eg = Eo
g – 0.0592 pH
52. Application of glass electrode
Determination of pH:
Cell: SCE │Test solution ║ GE
E cell = Eg – Ecal.
E cell = Eo
g – 0.0591 pH – 0.2422
pH = Eo
g -Ecell – Ecal. / 0.0591
53. 53
A glass electrode dipped in a soln. of pH = 4 offered an
emf of 0.2066 V with SCE at 298 K. When dipped in a
soln. of unknown pH at the same temperature, the
recorded emf was 0.1076 V. Calculate the pH of the
soln. [ESCE = 0.2412 V].
pH= (Eg
o− Ecell − Ecal(decinormal) ) / 0.0591
4=( Eg
o− 0.2066− 0.3335) /0.0591
Eg
o= 0.7765 V
pH= ( 0.7765− 0.1076−0.3335) / 0.0591
pH= 5.67
54. Q-1
KCl solution is used to make salt bridge because
• KCl is highly soluble in water
• To increase liquid junction potential
• Mobilities of K+ and Cl- are nearly the same
• Mobility of K+ is greater than Cl-
Which of the following statements is incorrect?
• An external power supply is needed in an electrolytic cell.
• In a galvanic cell difference between the electrode potentials of two
electrodes is responsible for the flow of electrons between the two half
cells.
• The electrode with a higher standard electrode potential will undergo
reduction with respect to other electrode.
• In a galvanic cell, the passage of a current through the electrolytes
drives a redox reaction.
Which of the following factors will not affect appreciably the emf of the cell?
• 1. Nature of the electrode
• 2. Concentration of the electrolyte
• 3. Temperature
• 4. Liquid junction potential 54
55. Q-2
The EMF of the following cell is found to be 0.20 V at 298 K,
Cd(s)/Cd2+(aq)(?)// Ni2+ (aq) (2.0 M)/Ni (s)
What is the molar concentration of Cd2+ ions in solution?
• 1. 4.00 M -0.25 + 0.40 = 0.15 V
• 2. 0.040 M
• 3. 0.400 M Eo
Cd2+/Cd = − 0.40 V
• 4. 0.004 M Ni2+/ Ni = - 0.25 V
Ans:
55
R
P
log
nF
RT
303
.
2
-
E
E 0
cell
cell
2
x
log
2
/
0591
.
0
-
0.15
20
.
0
2
x
log
2
/
0591
.
0
-
05
.
0
log2
-
[logx
0591
.
0
-
1
.
0
log2
-
[logx
692
.
1
[logx
3010
.
0
692
.
1
[logx
391
.
1
M
0.04
X
56. If E1, E2 and E3 are the emf values of the following three galvanic cells
respectively
Mg|Mg2+(0.02 M)||Cu2+(0.2 M)|Cu
Mg|Mg2+(0.2 M)||Cu2+(0.2 M)|Cu
Mg|Mg2+(0.1 M)||Cu2+(0.2 M)|Cu
Which one of the following is true?
• E3>E2>E1
• E1>E3>E2
• E1>E2>E3
• E2>E3>E1
Q-2
R
P
log
nF
RT
303
.
2
-
E
E 0
cell
cell
0.2
0.2
log
0.0295
-
[2.71]
E2
(-1)
log
0.0295
-
2.71
E1
0.0295
2.71
E1
2.7395
E1
0.2
0.02
log
0.0591/2
-
(-2.37)]
-
[0.34
E1
2.71
E2
0.2
0.1
log
0.0295
-
[2.71]
E3
(-0.3010)
log
0.0295
-
2.71
E3
2.7188
E3
57. 57
Q-2
Which among the following combinations of electrodes in 1M concentration of itꞌs
salt solution at 298K produce maximum emf?
(Given Eo of Fe3+ = 0.77 V, Cu2+ = 0.34 V, Sn2+ = -0.14 V and Mg2+ = -2.37 V)
1. Fe3+ and Sn2+
2. Cu2+ and Mg2+
3. Fe3+ and Mg2+
4. Cu2+ and Sn2+
A standard cell has a
1) 0.0V potential at 298K
2) Negligible temp. coeff. Of emf
3) 1.0V potential at 298K
4) high temp. coeff. Of emf
0.91
0.14)
(-
-
0.77
E
2.71
2.37)
(-
-
0.34
E
3.14
2.37)
(-
-
0.77
E
0.48
0.14)
(-
-
0.34
E
58. Q-2
What is EoNi2+/Ni at 298 K if the emf of Zn(s)/Zn2+(1M)││Ni2+(1M)/Ni(s) is 0.51V and
Zn(s)/Zn2+(1M)││SCE is 1.002V (ESCE = 0.2422V).
1. 0.7568
2. -1.2698
3. 1.2442
4. -0.2498
Zn
calomel
cell E
-
E
E
Zn
E
-
0.2422
1.002
0.7598
-
EZn
Ecell = Ec-EA
0.51 = Ec- (- 0.7598)
0.51 = Ec+ 0.7598
-0.2498 = ENi2+/Ni
ENi2+/Ni = E0Ni2+/Ni -0.059 /2 log 1/1
= -0.2498V
59. 59
The standard free energy change in joules of the following cell at 300 K.
Cu(s) / Cu2+(0.1M)║Ag+(0.25M) / Ag(s); Eocell = 0.46 V
1. -88,780
2. -44,390
3. 88,780
4. 44,390
Q-2
ΔG° = -nFE°
= -2×96500×0.46 = -88,780 J
60. 60
Saturated calomel electrode is called as a secondary reference electrode because
1. Its potential depends on the concentration of KCl used
2. Its potential is fixed as zero volt
3. Its potential is constant and measured with respect to primary reference
electrode
4. Mercurous chloride decompose above 50° C
Calomel electrode is an example of
1. Redox electrode
2. Metal insoluble salt electrode
3. Ion selective electrode
4. Gas electrode
Q-2
61. 61
Calculate the free energy of Cu electrode with Cu2+ concentration 0.015 M.
1. -44816 J
2. -55217 J
3. -65620 J
4. -65260 J
Q-2
E = E° - 0.0591/2 log1/[Cu2+)
= 0.34-0.0591/2 log 1/0.015 = 0.2861 V
ΔG = -nFE = -2×96500×0.2861
= -55217 J
The emf of a cell, Pt | H2 | H+ (x) || KC l |Hg2Cl2 | Hg is 0.83V at 298K.
Then the pH of the unknown solution is
1) 8.9
2) 9.9
3) 4.11
4) 5.02
pH = (Ecell – 0.2422)/0.0592
= (0.83-0.2422)/0.0592
= 9.9
62. Q3
Calculate the standard emf in volts for a cell
containing Sn2+ / Sn and Br2 / Br - electrodes.
[ Eo ( Sn2+ / Sn) = − 0.14 V, Eo ( Br2 / Br -) = 1.08 V]
E o cell = E o cathode − Eo anode
Because reduction potential of Eo ( Br2 / Br-) is
higher, it is cathodic
E o cell = Eo ( Br2 / Br -) - Eo ( Sn2+ / Sn)
= 1.08 – (− 0.14)
= 1.22 V
62
63. Q3
Using the electrochemical series, calculate the emf in volts for the cell
Fe(s) | Fe2+(0.1 M) || Cd2+(0.2 M) | Cd at 298 K. Write the cell reactions.
From the series we have;
Eo Cd2+/Cd = − 0.40 V ; Eo Fe2+/Fe = − 0.44 V
At anode Fe →Fe2+ + 2 e−
At Cathode Cd2+ + 2 e− → Cd
Net reaction: Fe + Cd2+→ Fe2+ + Cd
EMF of the cell at 298 K is given by
Eocell = Eocathode − Eo anode
= − 0.40 − (− 0.44)
= 0.04 V
Ecell = Eocell − (0.0591 / n) log [ Fe2+ ] / [Cd2+]
= 0.04 −( 0.0591/ 2 ) log [0.1] / [0.2]
= 0.0488 V
63
64. Q3
Find the molar concentration of Cd2+ ions in the given electrochemical cell.
Zn / Zn2+ (0.1 M) // Cd2+(M)/ Cd
Given Eo Zn2+/Zn = − 0.76 V; Eo Cd2+/Cd = − 0.40 V ; and Ecell = 0.3305 V at
298 K
Cell representation
Zn│Zn2+(1M)││Ag+(10M)│Ag
Cell reaction:
Zn + 2Ag+ → Zn2+ + 2Ag
Eo
cell = Eo
cathode − Eo
anode
= 0.80 − ( −0.76) = 1.56 V
Ecell = E°cell − (0.0592/ 2) log [1]/[10]2
= 1.56 – (0.0591 /2) log [1] / [10]2
= 1.6192 V
64
65. Q3
Write the cell reactions and calculate the EMF in volts for the following
cell at 298K.
Mg/ Mg2+ (0.001M) // Cu2+ ( 0.0001M) / Cu .
Given Eo Cu2+/Cu = 0.34 V and Eo Mg2+/Mg = − 2.37V
At anode Mg → Mg2+ + 2 e−
At cathode Cu2+ + 2 e− → Cu
Net reaction Mg + Cu2+ → Mg 2+ + Cu
Ecell = Eocell − (0.0591/n ) log [ Mg2+]/ [Cu2+]
Eocell = Eocathode − Eo anode
= 0.34 – [ −2.37]
= 2.71V
Ecell = 2.71 – (0.0591 /2) log [0.001]/ [0.0001]
= 2.6805 V
65
66. Q3
Emf of Weston Cadmium cell is 1.0183 V at 293 K and 1.0l81 V at 298 K.
Calculate ∆G, ΔH and ΔS of the cell reaction at 298 K.
∆G = - n FE
n = 2 for the cell reaction;
F = 96,500 C E= 1.0181 V at 298 K
∆G = -2 x 96,500 x 1.0181 J = -196.5 KJ
∆H = nF [ T (δE /δT)P – E]
(δE/δT)p = 1.0181 – 1.0183 / 298-293 = -0.0002 / 5
= - 0.00004VK-1
T = 298 K
∆H = 2 x 96,500 { [298 x (-0.00004)] – 1.0181}
= -198. 8 KJ
ΔS = nF(δE / δT) P
= 2 x 96,500 x (0-00004) = -7.72JK-1
66
68. Q4
The emf of a cell consisting of a hydrogen and
the normal calomel is 0.664 V at 25 ºC. Calculate
the pH of the solution containing the hydrogen
electrode.
Ecell= Ecal (normal) – (−0.0591pH)
0.664 = 0.2810+0.0591 pH
0.383=0.0591 pH
pH= 6.48
68
69. Q4
A glass electrode dipped in a soln. of pH = 4 offered an
emf of 0.2066 V with decinormal calomel electrode at
298 K. When dipped in a soln. of unknown pH at the
same temperature, the recorded emf was 0.1076 V.
Calculate the pH of the soln. [CE = 0.2412 V].
pH= (Eg
o− Ecell − Ecal(decinormal) ) / 0.0591
4=( Eg
o− 0.2066− 0.3335) /0.0591
Eg
o= 0.7765 V
pH= ( 0.7765− 0.1076−0.3335) / 0.0591
pH= 5.67
69
70. Q4
Write the cell scheme and determine the electrode
potential of zinc immersed in 0.1 M ZnSO4. Given
E.M.F. of cell =1.0022 V and Eo (Calomel electrode)
=0.2422V.
Zn / ZnSO4( 0.1M) // KCl; Hg2Cl2;Hg
Ecell = E cathode – E anode
1.0022 = 0.2422 – E Zn2+ / Zn
E Zn2+ / Zn = 0.2422 – 1.0022
= - 0.76 V
70