Some terms used in electrochemistry are :
1. Electro chemistry
It is a branch of chemistry which deals with the relationship between electrical energy and chemical energy.
Like heat energy and light energy, electric energy may bring about a chemical reaction. Also, electric energy can be produced by a chemical reaction. A setup in which the passage of electricity causes a chemical reaction to occur or one in which a chemical reaction produces electric energy is called an electrochemical cell Electrochemical cells are of two types: electrolytic cell and galvanic cell.
In electrolytic cell, flow of electricity through a solution causes a chemical reaction. This process in the electrolytic cell is called electrolysis.
In a galvanic cell (or voltaic cell), electricity is produced from a chemical reaction.
A liquid that conducts electricity due to the presence of positive and negative ions is called an electrolyte. An electrolyte can be a solution of a compound in water, or a molten ionic compound. Examples of electrolytes are: solutions of ionic compounds (e.g., NaCl), acids, alkalis, molten sodium chloride, etc.
Note Mercury, a liquid, conducts electricity, but it is not considered an electrolyte because conduction in it is due to electrons and not through ions.
A piece of material used in an electrochemical cell to conduct electric current is called an electrode. The anode is the electrode at which oxidation takes place and the cathode is the electrode at which reduction takes place.
4. Electrode potential
When a metal is placed in a solution containing ions of the metal, a voltage difference develops between the metal and the solution. This is called electrode potential. An electrode potential is also established between a metal and any electrolyte. The difference between the two electrode potentials produces the electromotive force (emf) of a galvanic cell.
5. Electromotive Force (emf) of the cell
A cell consists of two electrodes. The difference of potentials between the two electrodes is known as the electromotive force of the cell. Thus, emf is the electrical force of a cell which drives current through a connected circuit. In other words, emf is the cause of flow of electrons in the external circuit.
Electromotive force of the cell is symbolized by E and is measured in volts.
The process of decomposition of an electrolyte, by passing an electric current from an outside source through it, is known as electrolysis. For example, when an electric current is passed through acidified water, water is decomposed into hydrogen and oxygen.