Chemistry

Air Pollution: Gaseous Pollutants * Pollution is the harmful effect on the environment that can prove fatal to all living organisms. * Pollutants can be solid, liquid or gaseous, and originate from human actions and natural sources. * Air pollution takes place in two different layers of the earth’s atmosphere – the troposphere and the ... Read more

Classification * Hydrocarbons are organic compounds containing only hydrogen and carbon. * They play important role in our life as they meet more than 90 percent of the energy requirements of the world. Also they are the major sources of various other organic compounds which find use in different walks of life. * On the ... Read more

Introduction and Vital Force Theory * Carbon exhibits tetravalency. * Carbon has the ability to successively bond to other carbon atoms to form long chain. This property of carbon is called as catenation. *Carbon also forms covalent bonds with hydrogen, oxygen, nitrogen, sulphur and halogens. These complex carbon compounds are known as organic compounds. * ... Read more

Group 13: General trends and Properties * Group 13 through 18 of the periodic table are called the p-block because the outermost electrons occupy p-orbitals. * Non-metals and metalloids are located in the p-block, as well as some metals. * The elements in period 3 and below can have expanded octets by involving d-orbitals in ... Read more

Alkali Metals: General Characteristics and Properties * The group1 metals are called the alkali metals. They are the most reactive metals. * They all have 1valence electron and all form +1 cations. * The alkali metals are good conductors, and they have a shiny, silvery appearance. * In flame tests, lithium forms a candy-apple red ... Read more

Dihydrogen: Preparation * Hydrogen is the most abundant element in the universe. * It has three isotopes – protium, deuterium and tritium. * In spite of its resemblance to both alkali metals and halogens, it occupies a separate place in the periodic table due to its unique behavior. * Its unique behavior also makes it ... Read more

Classical Concept * In a redox reaction oxidation and reduction occurs simultaneously. * Oxidation reactions are those reactions which include addition of oxygen or an electronegative element to a substance or removal of hydrogen or an electropositive element from a substance. * Reduction reactions are those reactions which include removal of oxygen or an electronegative ... Read more

Physical processes: Equilibrium * Equilibrium is a condition in which two opposing tendencies balance one another. * The opposing tendencies of a reversible change continue to take place with equal rates simultaneously at the equilibrium stage also. Hence, the equilibrium is called dynamic equilibrium. * Equilibrium can be established for physical as well as chemical ... Read more