Glossary E

Electrolysis

A method of separating bonded elements and compounds by passing electricity through them.   The process is performed in a container called an electrolytic cell.   The source material is dissolved in an electrolyte so that constituent ions are available in the solution.   An electrical potential (voltage) is applied across a pair of conductors immersed in an electrolyte by a generator or battery.   The negatively charged conductor is called the cathode, and the positively charged conductor is called the anode.   Each conductor attracts the ions of the opposite charge; therefore, positively charged ions (cations) move towards the cathode while negatively charged ions (anions) move to the anode.   The energy required to separate the ions, and increase their concentration at the electrodes, is provided by the electrical power supply (battery or generator) that maintains the potential difference across the electrodes.   At the electrodes, electrons are absorbed or released by the ions, forming concentrations of the desired element or compound.   For example, when water is electrolyzed, hydrogen will form at the cathode, and oxygen at the anode. This was first discovered by William Nicholson, an English chemist, in 1800.   Note that in electrolysis, electrical energy is converted into chemical energy.

In 1832, Michael Faraday reported that the quantity of elements separated by passing an electrical current through a molten or dissolved salt was proportional to the quantity of current passed through the circuit. This is known as the first law of electrolysis.   Faraday also discovered that the weight of the resulting separated elements was directly proportional to the atomic weights of the elements when an appropriate integral divisor was applied.   This is the second law of electrolysis.   This experiment provided strong evidence that discrete particles of electricity existed as parts of the atoms of elements.   Electrolysis is used in the manufacture of aluminium, lithium, hydrogen, chlorine, aspirin, and other materials. ^{Wiki n.p.}   It is also used cosmetically in the removal of unwanted hair.   Italian chemist, Luigi V. Brugnatelli invented electroplating in 1805 by depositing gold on another metal using a Voltaic Pile, an early type of battery.

Electrolyte

An ionized solution or molten metallic salt acting as an electrical conductor where electricity is carried by ions rather than by free electrons, as in a metal.   Electrolytes include water solutions of acids, bases, or salts; certain pure liquids; and molten salts.   Gases may be electrolytes under high temperature or low pressure.   All inorganic acids, bases, and salts are electrolytes.   They are classified as strong or weak according to how readily they dissociate into conducting ions.   Potassium chloride and sodium hydroxide are strong electrolytes, whereas acetic acid is a weak electrolyte.   An electrolyte is decomposed into ions when a current passes through it, which forms the basis of electrolysis, important in electroplating and the separation of elements and compounds. ^{Ency n.p.}   Sodium and potassium ions are essential to human metabolism.

Electroplating

A form of electrolysis, where a metal is coated with another metal to enhance its properties.     It is also called electro-deposition.   The plating metal is generally the anode, and the object to be plated is the cathode.   The electrolyte is a solution of a salt of the plating metal.   The plating metal is deposited on the cathode, and the anode replenishes the supply of positive ions, thus gradually being dissolved.   Electrotype printing plates, silverware, jewelry, chrome automobile trim and other materials are frequently electroplated. ^{Ency n.p.}   Electroplating differs from anodizing in that with anodizing, the material to be coated is at the anode rather than at the cathode.   However, they both use the same process.   A similar, undesirable electrolytic action, called electrolytic corrosion, occurs in water with an abundance of naturally occurring ions, such as sea water or pipes laid underground.   The iron or other metal in a boat, ship or pipe becomes the anode to another metal acting as the cathode and proceeds to disintegrate.   The problem can be solved by supplying a metal higher in the activitiy series (e.g., Mg) that acts as the "sacrificial anode", the good metal, like iron, becoming the cathode.   As the sacrificial metal gradually wears away, it will have to be replaced.

England

The first king of England was Egbert, who united the realms of Wessex, Cornwall, Mercia, Kent, Sussex, Essex and East Anglia in the 9th century and gave them the name England.   His descendents ruled England until Canute the Great, a Danish king, assumed control of the country.   The Saxon line was restored under Edward the Confessor before the William the Conqueror became the first Norman king of England in 1066.   William did not conquer Wales, however.   Union of Wales with England was achieved by the Statute of Rhuddlan in 1284, but formal recognition was made by the Act of 1536.

Politically, Great Britain ("great" here meaning "big") consists of the nations of England, Scotland and Wales, including a number of smaller islands such as Anglesey, the Isle of Wight, the Hebrides, the Orkney Islands, the Shetland Islands, the Faroe Islands and the Isle of Man.   An older name for the island of Great Britain is Albion, which is still used in American English, including the form Albany. The United Kingdom includes part or all of the Ireland.   It excludes the Isle of Man, the Channel Islands, and the Bailiwicks of Jersey and Guernsey, which are "Crown dependencies".   The British Isles is a geographical name, not a political one.   They consist of Great Britain, the whole of Ireland, the Orkney and Shetland Islands, the Isle of Man, the Inner and Outer Hebrides, the Isle of Wight, the Scilly Islands, Lundy Island, the Channel Islands and many other smaller islands.

On March 26, 1707, an Act of Union joined England and Scotland, creating Great Britain or sometimes, The Kingdom of Great Britain.   Thereafter, England did not exist as a political entity, only as a geographical one.   On January 1, 1801, under a new Act of Union, this kingdom merged with the Kingdom of Ireland, and was called the United Kingdom of Great Britain and Ireland (United Kingdom, for short).   The United Kingdom does not include the Isle of Man or the Channel Islands.   On December 6, 1922, twenty-six of Ireland's thirty-two counties were joined to form a separate Irish Free State.   The remaining kingdom is now known as the United Kingdom of Great Britain and Northern Ireland, which includes a number of Overseas Territories.