Al dissolves in hot aqueous alkali ( lithium, sodium, and potassium) to form − and hydrogen. Dilute and concentrated nitric acid render aluminum passive by forming a protective oxide layer.Al is scarcely attacked by dilute sulfuric acid but concentrated acid is reduced to sulfur dioxide.For example, Al and Ga dissolve in aqueous hydrochloric acid giving M +3 ions but Tl does not due to the instability of TlCl.All the elements of Group 13 have different chemical properties and reactivity. If the film is removed by amalgamation, water forms. It is not attacked by water owing to the presence of a protective coating. The surface of the electrolyte was covered with a layer of coke, which oxidized evolving oxygen for the protection of valuable electrodes. The molten aluminum sinks to the bottom of the cell and drained out. The electrode reaction for the production of aluminum,Ĭathode: 2 Al +3 + 6e → 2 Al Anode: 3 O −2 → 3 O + 6e Purified bauxite (melting point 2050 ☌) is dissolved in cryolite and electrolyzed at 950 ☌ in carbon lined steel cells.Ī mixture of cryolite, CaF 2, AlF 3, Al 2O 3, Li 2CO 3 in the electrolyte is used because it has a lower melting point, permits larger current flow, and reduces fluorine emission. It can be produced electrolytically from bauxite in electrochemical cells. Commercial production of the element started in 1954 by electrolysis of NaAlCl 4. In 1825 Denmark physicist Hans Christian Orsted first discovered the metal by reducing aluminum chloride (AlCl 3) with potassium amalgam. Who discovered aluminum?Īlum was the compound of aluminum widely used in Rome for the production of different types of medicine and dyes in textiles.īritish chemist Sir Humphry Davy failed to isolate the metal but suggested the name of the element aluminum or alumium. Rich deposits of bauxite are found in Australia, Brazil, Guinea, Jamaica, France, United States, Russia, India, and several African counties. A workable bauxite sample contains 40 to 60 percent metal aluminum oxide (Al 2O 3), 12 to 30 percent water, 1 to 15 percent iron oxide (Fe 2O 3), and 3 to 4 percent titanium oxide (TiO 2). The chief commercial source of metallic aluminum is hydroxo oxide like Al 2O 3, xH 2O, or bauxite. Oxide like Corundum (Al 2O 3) is used in Gems (ruby, sapphire) due to its hardness. The most important minerals found in nature as oxide and anhydrous hydrated oxides. The only fluoride mineral is cryolite (Na 3AlF 6), found in Greenland. ![]() The most abundant element, aluminum found in various silicate minerals like mica, feldspar, kaolinite, and clay. It is a metalloid that lies between boron and gallium. ![]() Aluminum in the periodic tableĪluminum is found in group 13 and period 3 of the periodic table. Due to large ionization energy not compensated by weak lattice energy, it commonly attains a +3 state by covalent bonding. ![]() Due to decreases in lattice energy with increasing size, aluminum should be likely to form an Al +3 ion. The common oxidation number or states of metal +1 +2 and +3. The Latin word for alum alumen means bitter salt The name aluminum comes from the Latin word alumen, which describes the aluminum potassium sulfate, KAl(SO 4) 2, 12H 2O. Properties of aluminumįace-centered cubic crystal lattice (fcc), aluminum has the chemical symbol Al, atomic number 13. It forms intermetallic aluminum compounds with a large number of metals. It combines most of the nonmetallic elements like nitrogen, sulfur, and halogens. It is the most abundant metallic element in the earth’s crust (8 percent by weight).Īl differs from the first member of Group 13 (boron) due to its chemical properties, high reactivity, and cationic chemistry in an aqueous solution.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |