Class 11 Chemistry Ch 10 Notes

• Definition of Electrochemistry
• Difference between Electronic Conduction and Electrolytic Conduction: 1. This type of conduction is present in metals 1. This type of conduction is present in molten salts or their aqueous solutions 2. This conduction is due to the movement of free electrons present in metals 2. This conduction is due to the movement of positive and negative ions 3. No physical or chemical change take place in conductor during electronic conduction 3. Ions undergo oxidation and reduction reactions at respective electrodes 4. Example: copper, iron etc 4. Example: Electrolysis of molten NaCl to Cl2 and Na.
• Definition of Electrochemical Cells
• Definition of Electrolytic cells: “An electrochemical cell in which electric current is used to drive a non-spontaneous reaction is called electrolytic cell”.
• Electrolysis of aqueous solution of salts (using inert electrodes)
• Examples of electrolysis (When electrodes take part in reaction)
• Electrolytic processes of Industrial Importance
• Define Voltaic or Galvanic Cell with its construction
• Define Electrode Potential: The potential set up when an electrode is in contact with one molar solution of its own ions at 298 K is known as standard electrode potential or standard reduction potential of the element. It is represented as E°. Method of determination When a metal strip is placed in a solution of its own ions, there are two tendencies. 1. The metal atoms may dissolve as positive ions. The electrons are deposited on the metal electrode. 2. The metal ions present in solution may take up electrons from the metal and get discharged as atoms. It imparts a positive charge to the metal. Outcome In both cases, a potential difference is set up between the metal and the solution which is called single electrode potential.
• Determination of electrode potential with reference hydrogen electrode: 1. Arbitrary scale Standard electrode potential of hydrogen has arbitrarily been chosen as zero. 2. Comparison with hydrogen electrode The standard electrode potentials of other elements are found by comparing them with standard hydrogen electrode potential. 3. Equilibrium between atoms and ions The electrode potential set up when a metal piece is placed in a solution containing its own ions can be explained in terms of equilibrium between the atoms of the metal and its ions in solution. 4. Formation of positive ions When a metal is placed in a solution, some of its atoms tend to give electrons to the piece of metal and pass into the solution as positively charged ions. 5. Formation of neutral atoms The metallic ions already present in solution tend to take up electrons from the piece of metal and deposit themselves as neutral atoms. 6. Factor deciding charge. Whichever tendency is greater determines whether the metal becomes negatively or positively charged. 7. No potential difference change When equilibrium is attained the two opposing processes continue at the same rate and there is no further change in the potential difference. Example A rod of zinc will bear an accumulation of negative charges. This is due to the net ionization of some of its atoms. Electrical double layer The negative charge on the Zn-rod will attract an atmosphere of positively charged zinc ions around the rod to form an electrical double layer.
• Measurement of Electrode Potential
• Establishment of galvanic cell
• Example of galvanic cell between zinc and hydrogen
• Example of galvanic cell between copper and hydrogen
• Define The Electrochemical Series and Applications of Electrochemical Series
• Calculation of the Voltage or Electromotive Force (EMF) of Cells
• Comparison of Relative Tendency of Metals and Non-Metals to Get Oxidized and Reduced
• Relative Chemical Reactivity of Metals with examples
• Modern Batteries and Fuel Cells and Principle of working and battery design
• Definition of Fuel Cells and Principle of working
• What is standard hydrogen electrode (SHE)? How it is used to measure the electrode potential of Zinc.
• Describe the electrolysis of molten sodium chloride and a concentrated aqueous solution of sodium chloride.
• Explain the construction and working of fuel cell.  Write a note on fuel cells.
• Give explanation of discharging and recharging of lead accumulator along with reactions occurring at electrodes.