Electrode Potential and Standard Electrode Potential are key concepts in the field of electrochemistry which is the branch of chemistry that deals with relationships between electric potential differences and observable chemical change.
Electrode Potential is also used extensively in the development of sustainable battery technologies, as all modern-day batteries work on this principle to create voltage for the smooth operations of electronic gadgets.
Table of Contents
What is Redox Reaction?
When in any reaction, both process i.e., oxidation and reduction; happens simultaneously, that reaction is called a redox reaction.
For example, in zinc-copper cell
Oxidation Half-Reaction at Anode
Zn(s) → Zn2++2e–
Reduction of Half-Reaction at Cathode
Cu2++2e– → Cu(s)
To make metallic copper, zinc loses electrons that are grabbed by copper ions. The entire redox reaction between zinc and copper is:
Cu2++ Zn(s) → Cu(s) + Zn2+
The Redox Process in Zinc and Copper Cells was observed.
What is Electrode Potential?
In each half-cell, electrons move between the electrodes through the electrolyte. This movement of charge creates a potential known as Electrode Potential. Electrode Potential can be categorized into two types: Oxidation Potential and Reduction Potential. Let’s understand each of them:
Oxidation Potential: It represents the tendency of a metal (M) to undergo oxidation by losing electrons (ne–) and forming metal ions (Mn+). This process is denoted as
M → Mn+ + ne–
Reduction Potential: It represents the tendency of metal ions (Mn+) to gain electrons (ne–) and convert them back into the original metal (M). This process is denoted as
Mn+ + ne– → M
Factors Affecting Electrode Potential
There are various factors affecting the electrode potential, some of those factors are as follows:
Nature of Electrolyte: The presence and concentration of ions in the solution affect the activity or effective concentration of the species involved in the redox reaction, thus impacting the electrode potential.
Temperature: As temperature increases, the kinetic energy of the reacting species also increases, leading to faster reaction rates. The Nernst equation represents the changes in temperature that can affect the overall electrode potential.
Pressure: For gaseous electrode reactions, increasing the pressure increases the concentration of the gaseous species, which alters the electrode potential accordingly.
Surface Area of Electrode: A larger surface area provides more sites for redox reactions to occur, resulting in an increased electrode potential and a larger surface area of the electrodes also makes the transfer of electrons more efficient.
pH and Concentration of Electrolyte: pH of the electrolyte solutions affects electrode potential, especially for those electrodes which involve hydrogen ions. Changing pH is nothing but a change in the concentration of hydrogen ions, and a change in concentration changes the rate of reaction.
How to Calculate Electrode Potential
The electrode potential can be calculated using the following formula:
E∘cell = E∘red – E∘oxid
The half-cell with the larger reduction potential goes through the reduction process, whereas the half-cell with the lower reduction potential goes through the oxidation process.
Standard Electrode Potential
As we already discussed that the potential difference between the metal and its solution is known as the electrode potential. If the concentration of the participating species in the electrode reaction is unity and the reaction occurs at 298K and 1 atm pressure, the electrode potential is referred to as Standard Electrode Potential (E0).
How to measure Standard Electrode Potentials?
The standard electrode potential (E0) of hydrogen gas, in the case of the convention, is 0.00 volts. The redox couple is a stronger reducing agent than the H+/H2 couple when the standard electrode potential is negative. On the other hand, a positive standard electrode potential suggests that the redox couple is a weaker reducing agent than the H+/H2 pair.
Applications of Electrode Potential
There are various use cases for electrode potential and standard electrode potential, some of these use cases are as follows:
It may be used to investigate processes like corrosion and pitting, as well as control the reaction process.
The Electrode Potential can be used to help choose materials and equipment for reaction control.
Corrosion caused by electrochemical and chemical reactions and processes can be predicted with this tool.
Sample Questions on Electrode Potential
Question 1: What processes are involved in redox reactions?
Answer:
A redox process is an electron transfer reaction that involves both reduction and oxidation, with reduction being the intake of electrons and oxidation being the release of electrons.
Question 2: How does a redox reaction produce electricity?
Answer:
A galvanic cell, also known as a Voltaic cell, is an electrochemical cell that generates electrical energy through a redox reaction or redox process. A voltaic cell is made up of two half-cells that perform either the reduction or oxidation processes.
Question 3: How Electrolysis is an example of a redox reaction?
Answer:
Electrolysis is a redox reaction because reduction occurs at the cathode and oxidation occurs at the anode, and both of these reactions occur at the same time.
Question 4: What does the reduction process do?
Answer:
Chemical entities lose electrons during the reduction process, lowering their oxidation number. The oxidation part of the reaction involves the loss of electrons. Reduction is the polar opposite of oxidation.
Cu2++2e– → Cu(s)
Question 5: What is a redox couple example?
Answer:
In redox reactions, a redox pair is formed by the oxidised and reduced versions of each reactant. Redox couples are denoted as “Ox/red.” For example- Cu2+/Cu and Zn2+/Zn, have an oxidised version on the left and a reduced version on the right, separated by a slash.
Question 6: What are the uses of electrode potential?
Answer:
It helps with corrosion and pitting investigations, as well as reaction control.
Electrode Potential can be used to help choose materials and equipment for reaction control.
Corrosion caused by electrochemical and chemical reactions and processes can be predicted with the help of this programme.
FAQs on Electrode Potential
What is Electrode Potential?
Electrode potential is the measure of tendency of an electron to undergo a reduction or oxidation reaction, due to this fact it is also called redox potential.
What does Electrode Potential represent?
Electrode Potential represents the potential difference between an electrode and its surrounding solution when no current is flowing through the electrode.
How is Electrode Potential measured?
Electrode potential is measured using a reference electrode which has known and stable potential. To measure electrode potential
is typically measured using a reference electrode, which has a known and stable potential. The reference electrode is connected to the electrode of interest, and the potential difference between the two electrodes is measured using a voltmeter or a potentiostat.
What is standard electrode potential?
Standard electrode potential is the potential difference between an electrode and its surrounding solution when the concentration of all species involved in the electrode reaction is 1 M, the temperature is 25°C (298 K), and the pressure is 1 atm. Standard electrode potentials are tabulated and used as reference values to compare the reactivity of different electrodes which is known as electrochemical series.
How are standard electrode potentials determined?
Standard electrode potentials are determined experimentally by measuring the electrode potential of a half-cell relative to a reference electrode under standard conditions. The half-cell reaction is balanced, and the potential is measured using a voltmeter. The measured potentials are then tabulated, and the values are standardized and widely accepted.
What is the significance of standard electrode potential?
Standard electrode potentials provide valuable information about the reactivity and relative strength of different redox couples or half-reactions. By comparing the standard electrode potentials of different electrodes, it is possible to predict the direction of electron flow in a redox reaction and determine the feasibility of a particular redox process.
How is the direction of electron flow determined using standard electrode potentials?
The direction of electron flow in a redox reaction can be determined by comparing the standard electrode potentials of the half-reactions involved. The reaction will occur spontaneously in the direction where the more positive electrode potential corresponds to reduction (gaining electrons), and the more negative electrode potential corresponds to oxidation (losing electrons).
What does a positive or negative standard electrode potential indicate?
A positive standard electrode potential (E° > 0) indicates that the reduction half-reaction is more favorable under standard conditions, and the electrode acts as a good oxidizing agent. A negative standard electrode potential (E° < 0) indicates that the oxidation half-reaction is more favorable under standard conditions, and the electrode acts as a good reducing agent.
How does temperature affect electrode potential?
Electrode potential is temperature-dependent. As temperature increases, electrode potentials generally change according to the Nernst equation, which relates the electrode potential to the concentration and activities of the species involved in the redox reaction. The Nernst equation allows for the calculation of the electrode potential under non-standard conditions.
Can electrode potential be altered or controlled?
Electrode potential can be altered or controlled by changing the concentration of reactants or by applying an external potential using an external power supply. These changes can shift the electrode potential away from its standard value and allow for the manipulation of redox reactions.
Neeraj Anand, Param Anand
Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations.
In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS".
He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.
CBSE Class 11 Chemistry Syllabus is a vast which needs a clear understanding of the concepts and topics. Knowing CBSE Class 11 Chemistry syllabus helps students to understand the course structure of Chemistry.
Unit-wise CBSE Class 11 Syllabus for Chemistry
Below is a list of detailed information on each unit for Class 11 Students.
UNIT I – Some Basic Concepts of Chemistry
General Introduction: Importance and scope of Chemistry.
Nature of matter, laws of chemical combination, Dalton’s atomic theory: concept of elements, atoms and molecules.
Atomic and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular formula, chemical reactions, stoichiometry and calculations based on stoichiometry.
UNIT II – Structure of Atom
Discovery of Electron, Proton and Neutron, atomic number, isotopes and isobars. Thomson’s model and its limitations. Rutherford’s model and its limitations, Bohr’s model and its limitations, concept of shells and subshells, dual nature of matter and light, de Broglie’s relationship, Heisenberg uncertainty principle, concept of orbitals, quantum numbers, shapes of s, p and d orbitals, rules for filling electrons in orbitals – Aufbau principle, Pauli’s exclusion principle and Hund’s rule, electronic configuration of atoms, stability of half-filled and completely filled orbitals.
UNIT III – Classification of Elements and Periodicity in Properties
Significance of classification, brief history of the development of periodic table, modern periodic law and the present form of periodic table, periodic trends in properties of elements -atomic radii, ionic radii, inert gas radii, Ionization enthalpy, electron gain enthalpy, electronegativity, valency. Nomenclature of elements with atomic number greater than 100.
UNIT IV – Chemical Bonding and Molecular Structure
Valence electrons, ionic bond, covalent bond, bond parameters, Lewis structure, polar character of covalent bond, covalent character of ionic bond, valence bond theory, resonance, geometry of covalent molecules, VSEPR theory, concept of hybridization, involving s, p and d orbitals and shapes of some simple molecules, molecular orbital theory of homonuclear diatomic molecules(qualitative idea only), Hydrogen bond.
UNIT V – Chemical Thermodynamics
Concepts of System and types of systems, surroundings, work, heat, energy, extensive and intensive properties, state functions. First law of thermodynamics – internal energy and enthalpy, measurement of U and H, Hess’s law of constant heat summation, enthalpy of bond dissociation, combustion, formation, atomization, sublimation, phase transition, ionization, solution and dilution. Second law of Thermodynamics (brief introduction) Introduction of entropy as a state function, Gibb’s energy change for spontaneous and nonspontaneous processes. Third law of thermodynamics (brief introduction).
UNIT VI – Equilibrium
Equilibrium in physical and chemical processes, dynamic nature of equilibrium, law of mass action, equilibrium constant, factors affecting equilibrium – Le Chatelier’s principle, ionic equilibrium- ionization of acids and bases, strong and weak electrolytes, degree of ionization, ionization of poly basic acids, acid strength, concept of pH, hydrolysis of salts (elementary idea), buffer solution, Henderson Equation, solubility product, common ion effect (with illustrative examples).
UNIT VII – Redox Reactions
Concept of oxidation and reduction, redox reactions, oxidation number, balancing redox reactions, in terms of loss and gain of electrons and change in oxidation number, applications of redox reactions.
UNIT VIII – Organic Chemistry: Some basic Principles and Techniques
General introduction, classification and IUPAC nomenclature of organic compounds. Electronic displacements in a covalent bond: inductive effect, electromeric effect, resonance and hyper conjugation. Homolytic and heterolytic fission of a covalent bond: free radicals, carbocations, carbanions, electrophiles and nucleophiles, types of organic reactions.
UNIT IX – Hydrocarbons
Classification of Hydrocarbons Aliphatic Hydrocarbons: Alkanes – Nomenclature, isomerism, conformation (ethane only), physical properties, chemical reactions. Alkenes – Nomenclature, structure of double bond (ethene), geometrical isomerism, physical properties, methods of preparation, chemical reactions: addition of hydrogen, halogen, water, hydrogen halides (Markovnikov’s addition and peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition. Alkynes – Nomenclature, structure of triple bond (ethyne), physical properties, methods of preparation, chemical reactions: acidic character of alkynes, addition reaction of – hydrogen, halogens, hydrogen halides and water.
Aromatic Hydrocarbons:
Introduction, IUPAC nomenclature, benzene: resonance, aromaticity, chemical properties: mechanism of electrophilic substitution. Nitration, sulphonation, halogenation, Friedel Craft’s alkylation and acylation, directive influence of functional group in monosubstituted benzene. Carcinogenicity and toxicity.
To know the CBSE Syllabus for all the classes from 1 to 12, visit the Syllabus page of CBSE. Meanwhile, to get the Practical Syllabus of Class 11 Chemistry, read on to find out more about the syllabus and related information in this page.
CBSE Class 11 Chemistry Practical Syllabus with Marking Scheme
In Chemistry subject, practical also plays a vital role in improving their academic scores in the subject. The overall weightage of Chemistry practical mentioned in the CBSE Class 11 Chemistry syllabus is 30 marks. So, students must try their best to score well in practicals along with theory. It will help in increasing their overall academic score.
CBSE Class 11 Chemistry Practical Syllabus
The experiments will be conducted under the supervision of subject teacher. CBSE Chemistry Practicals is for 30 marks. This contribute to the overall practical marks for the subject.
The table below consists of evaluation scheme of practical exams.
Evaluation Scheme
Marks
Volumetric Analysis
08
Salt Analysis
08
Content Based Experiment
06
Project Work
04
Class record and viva
04
Total
30
CBSE Syllabus for Class 11 Chemistry Practical
Micro-chemical methods are available for several of the practical experiments. Wherever possible such techniques should be used.
A. Basic Laboratory Techniques 1. Cutting glass tube and glass rod 2. Bending a glass tube 3. Drawing out a glass jet 4. Boring a cork
B. Characterization and Purification of Chemical Substances 1. Determination of melting point of an organic compound. 2. Determination of boiling point of an organic compound. 3. Crystallization of impure sample of any one of the following: Alum, Copper Sulphate, Benzoic Acid.
C. Experiments based on pH
1. Any one of the following experiments:
Determination of pH of some solutions obtained from fruit juices, solution of known and varied concentrations of acids, bases and salts using pH paper or universal indicator.
Comparing the pH of solutions of strong and weak acids of same concentration.
Study the pH change in the titration of a strong base using universal indicator.
2. Study the pH change by common-ion in case of weak acids and weak bases.
D. Chemical Equilibrium One of the following experiments:
1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing the concentration of either of the ions. 2. Study the shift in equilibrium between [Co(H2O)6] 2+ and chloride ions by changing the concentration of either of the ions.
E. Quantitative Estimation i. Using a mechanical balance/electronic balance. ii. Preparation of standard solution of Oxalic acid. iii. Determination of strength of a given solution of Sodium hydroxide by titrating it against standard solution of Oxalic acid. iv. Preparation of standard solution of Sodium carbonate. v. Determination of strength of a given solution of hydrochloric acid by titrating it against standard Sodium Carbonatesolution.
F. Qualitative Analysis 1) Determination of one anion and one cation in a given salt Cations‐ Pb2+, Cu2+, As3+, Al3+, Fe3+, Mn2+, Ni2+, Zn2+, Co2+, Ca2+, Sr2+, Ba2+, Mg2+, NH4+ Anions – (CO3)2‐ , S2‐, NO2‐ , SO32‐, SO2‐ , NO ‐ , Cl‐ , Br‐, I‐, PO43‐ , C2O2‐ ,CH3COO‐ (Note: Insoluble salts excluded)
2) Detection of ‐ Nitrogen, Sulphur, Chlorine in organic compounds.
G) PROJECTS Scientific investigations involving laboratory testing and collecting information from other sources.
A few suggested projects are as follows:
Checking the bacterial contamination in drinking water by testing sulphide ion
Study of the methods of purification of water.
Testing the hardness, presence of Iron, Fluoride, Chloride, etc., depending upon the regional variation in drinking water and study of causes of presence of these ions above permissible limit (if any).
Investigation of the foaming capacity of different washing soaps and the effect of addition of Sodium carbonate on it.
Study the acidity of different samples of tea leaves.
Determination of the rate of evaporation of different liquids Study the effect of acids and bases on the tensile strength of fibres.
Study of acidity of fruit and vegetable juices.
Note: Any other investigatory project, which involves about 10 periods of work, can be chosen with theapproval of the teacher.
Practical Examination for Visually Impaired Students of Class 11
Below is a list of practicals for the visually impaired students.
A. List of apparatus for identification for assessment in practicals (All experiments) Beaker, tripod stand, wire gauze, glass rod, funnel, filter paper, Bunsen burner, test tube, test tube stand, dropper, test tube holder, ignition tube, china dish, tongs, standard flask, pipette, burette, conical flask, clamp stand, dropper, wash bottle • Odour detection in qualitative analysis • Procedure/Setup of the apparatus
B. List of Experiments A. Characterization and Purification of Chemical Substances 1. Crystallization of an impure sample of any one of the following: copper sulphate, benzoic acid B. Experiments based on pH 1. Determination of pH of some solutions obtained from fruit juices, solutions of known and varied concentrations of acids, bases and salts using pH paper 2. Comparing the pH of solutions of strong and weak acids of same concentration.
C. Chemical Equilibrium 1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing the concentration of eitherions. 2. Study the shift in equilibrium between [Co(H2O)6]2+ and chloride ions by changing the concentration of either of the ions.
D. Quantitative estimation 1. Preparation of standard solution of oxalic acid. 2. Determination of molarity of a given solution of sodium hydroxide by titrating it against standard solution of oxalic acid.
E. Qualitative Analysis 1. Determination of one anion and one cation in a given salt 2. Cations – NH+4 Anions – (CO3)2-, S2-, (SO3)2-, Cl-, CH3COO- (Note: insoluble salts excluded) 3. Detection of Nitrogen in the given organic compound. 4. Detection of Halogen in the given organic compound.
Note: The above practicals may be carried out in an experiential manner rather than recording observations.
We hope students must have found this information on CBSE Syllabus useful for their studying Chemistry. Learn Maths & Science in interactive and fun loving ways with ANAND CLASSES (A School Of Competitions) App/Tablet.
Frequently Asked Questions on CBSE Class 11 Chemistry Syllabus
Q1
How many units are in the CBSE Class 11 Chemistry Syllabus?
There are 9 units in the CBSE Class 11 Chemistry Syllabus. Students can access various study materials for the chapters mentioned in this article for free at ANAND CLASSES (A School Of Competitions).
Q2
What is the total marks for practicals examination as per the CBSE Class 11 Chemistry Syllabus?
The total marks for the practicals as per the CBSE Class 11 Chemistry Syllabus is 30. It includes volumetric analysis, content-based experiment, salt analysis, class record, project work and viva.
Q3
Which chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry?
The organic chemistry chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry.
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