Electrochemistry Dr. Mamun Jamal Department of Chemistry Room no.: BECM 403 (main academic building) KUET

2 We will cover Lecture 1:Fundamentals Lecture 2: Electrolytic conductance, migration of ions and electrochemical cell Lecture 3: Reversible electrodes, electrode potentials, cell emf Lecture 4: Ionic mobilities, abnormal ion conductance, transport number and Kohlrauch’s law Electrochemistry

3 ‘Chemistry 1209’ CT1 will be on 25 th Nov 2015 Syllabus will be class lectures until 15 th Nov

4 Fundamentals of Electrochemistry Few definitions (i)Electrolytes, non electrolytes, electrolysis (ii)Galvanic cell and voltaic cell (iii)Half cell reaction and redox reaction (iv)Electrical units: coulomb, ampere, ohm, volt (v)Faraday’s Laws of electrolysis: first law and second law (vi)Conductance of electrolytes, specific conductance

5 Electrochemical cell (i)Electrolytic cell (ii) Voltaic cell or Galvanic cell

6 Cathod: is where reduction occurs Is where electrons are consumed Is what cations migrate toward Has a positive sign Anode: is where oxidation occurs Is where electrons are produced Is what anions migrate toward Has a negative sign

7 Data processing Glucose sensor Electrochemical cell Potentiostat

Basic Concepts 1.)A Redox titration is an analytical technique based on the transfer of electrons between analyte and titrant  Reduction-oxidation reaction  A substance is reduced when it gains electrons from another substance - gain of e - net decrease in charge of species - Oxidizing agent (oxidant)  A substance is oxidized when it loses electrons to another substance - loss of e - net increase in charge of species - Reducing agent (reductant) (Reduction) (Oxidation) Oxidizing Agent Reducing Agent 8 Fundamentals of Electrochemistry

Basic Concepts 2.)The first two reactions are known as “1/2 cell reactions”  Include electrons in their equation 3.) The net reaction is known as the total cell reaction  No free electrons in its equation 4.)In order for a redox reaction to occur, both reduction of one compound and oxidation of another must take place simultaneously  Total number of electrons is constant ½ cell reactions: Net Reaction: 9 Fundamentals of Electrochemistry