Electrochemistry

• Electrochemistry deals with the production of electric current through chemical reactions or chemical reactions produced by passing electric current through an electrolyte
• Electrochemical Cell is also known as voltaic or galvanic cell
• electrochemical cell converts chemical energy to electrical energy
• In electrochemical cell, Cell emf is positive, free energy change is negative and anode terminal is negative
• In Daniel cell, Zn electrode is the anode and Cu electrode is the cathode. Electrons generated at Zn electrode are consumed at Cu electrode.
• Salt Bridge or porous partition used for tranference of ions between the compartments in a Daniel Cell
• Salts like KCl and NH4NO3 are used for making the salt bridge. K+ and Cl- have equal mobility and gets drifted to cathode and anode compartments, respectively
• EMF value of Danie Cell = 1.1 V
• Electrolytic Cells convert electrical energy into chemical energy
• Volta Cell is an example for an irreversible cell. It consists of a Zn rod and Cu rod are dipped in a solution of dil. sulphuric acid.
• 5 types of electrodes are : Metal/Metal ion electrode, Gas electrode, Metal/insoluble metal salt/common ion electrode, redox electrode, ion selective electrode
• Metal / Metal ion Electrode - Metal immersed in its own salt solution
• Gas Electrode - Gas is passed through an inert electrode like Pt which is immersed in a solution containing its own ion
• Metal / Insoluble metal salt / Common ion electrode - Metal electrode covered with a paste of its insoluble metal salt which is in contact with a solution containing a common ion with insoluble metal salt
• Redox Electrode : Electrode like Pt in contact with a redox system
• Ion - selective Electrode : Sensing part is made of ion - specific membrane. Membrane can be glass membrane, crystalline membrane and ion - exchange resin membrane
• Conductivity is the reciprocal of specific resistance and is also known as specific conductance.
• Conductivity is defined as conductance of 1 cm3 of a conductor or solution held between two electrodes of area 1cm2 placed on opp. faces of a cube of side 1cm
• Conductance is the measure of ease with which current flows through a conductor.

  It is the reciprocal of resistance