OXIDATION AND REDUCTION
Chemical reactions in which the oxidation numbers of one or more atoms or elements change are known as oxidation-reduction or redox reactions. Oxidation occurs when the atom decreases. Oxidation involves the loss of electrons while reduction. In any redox reaction, oxidation of a substance requires the reduction of another. The oxidizing agent causes the oxidation process; it is the substance that is reduced. The reducing agent brings about the reduction process. It is the substance oxidized. Redox reactions are frequently encountered in the environment and in industrial processes. Reactions used in energy production are often oxidation-reduction reactions. The metabolism of foods, which supplies living organisms with energy, occurs by a series of redox reactions. The energy supply used by consumers is obtained from the oxidation of fossil fuels. The electricity generated by a battery to operate a pocket calculator is supplied by redox reactions. The production of iron in a blast furnace involves several oxidation-reduction reactions.
To be able to recognize some common oxidation-reduction reactions.
0.1M silver nitrate, AgNO3, copper wire, 0.1M potassium dichromate, K2Cr207, 3% hydrogen peroxide, H2O2, 3M sulphuric acid, H2SO4, 0.02M potassium permanganate, KMnO4, 0.1M iron(II) ammonium sulphate, Fe(NH4)2(SO4)2, 0.1M potassium thiocyanate, KSCN, 0.1M potassium iodide, Kl, 0.1M iron(III) chloride, FeCl3, 0.1M potassium ferricyanide, K3Fe(CN)6, carbon tetrachloride, CCl4/hexane, C6H14
Test tube, test tube rack, 10-mL graduated cylinder, medicine dropper
Observe and note the nature of the products. To indentify some of the products, consult the table below where certain properties of possible products are listed.
1. (a) Place a piece of copper wire in a test tube and add 2 mL of 0.1 M silver nitrate. AgNO3. Place the tube in the rack. (b) After several minutes,...