Notes On Electrochemical And Galvanic Cells - CBSE Class 12 Chemistry
An electrochemical cell is a device that is capable of either producing an electric current due to chemical action or of producing chemical action due to the passage of electricity. There are two basic types of electrochemical cells. They are voltaic or galvanic cells and electrolytic cells. In voltaic cells, the chemical energy of a spontaneous redox reaction is converted into electrical energy. Voltaic cells are also called galvanic cells. The electrical energy produced by such batteries can be put to useful work, powering our cell phones, radios and other devices. Oxidation is a loss of electrons. Reduction is a gain of electrons. Oxidation and reduction occur together. Oxidation occurs at the anode. Reduction occurs at the cathode. A salt bridge connects the solutions. The salt bridge allows migration of ions between the half-cells, while preventing direct contact between the half-cells. Standard electrode potentials are measured relative to the standard hydrogen electrode. The half-reaction with the more positive electrode potential will undergo reduction. The half-reaction with the more negative electrode potential will undergo oxidation. The potential difference between the two electrodes is called the cell potential (or) the cell electromotive force (or) emf. The potential of an individual half-cell cannot be measured directly but, measured in relative to an arbitrary standard, called the "standard hydrogen electrode".

#### Summary

An electrochemical cell is a device that is capable of either producing an electric current due to chemical action or of producing chemical action due to the passage of electricity. There are two basic types of electrochemical cells. They are voltaic or galvanic cells and electrolytic cells. In voltaic cells, the chemical energy of a spontaneous redox reaction is converted into electrical energy. Voltaic cells are also called galvanic cells. The electrical energy produced by such batteries can be put to useful work, powering our cell phones, radios and other devices. Oxidation is a loss of electrons. Reduction is a gain of electrons. Oxidation and reduction occur together. Oxidation occurs at the anode. Reduction occurs at the cathode. A salt bridge connects the solutions. The salt bridge allows migration of ions between the half-cells, while preventing direct contact between the half-cells. Standard electrode potentials are measured relative to the standard hydrogen electrode. The half-reaction with the more positive electrode potential will undergo reduction. The half-reaction with the more negative electrode potential will undergo oxidation. The potential difference between the two electrodes is called the cell potential (or) the cell electromotive force (or) emf. The potential of an individual half-cell cannot be measured directly but, measured in relative to an arbitrary standard, called the "standard hydrogen electrode".

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