CHAPTER I<br >INTRODUCTION<br >DeAnition，<br > Organic chemistry is the study of the compounds containing<br >carbon.<br >Composition，<br > Many different elements may occur in organic compounds but<br >the ones most commonly found， in the order of their relative<br >occurrence， are" carbon， hydrogen， oxygen， nitrogen， phosphorus，<br >sulfur， chlorine， bromine， and iodine.<br >Original Concept of Organic Chemistryt<br > It was formerly believed that organic compounds were ex-<br >clusively of plant or animal origin and that vital processes were<br >necessary for their formation. In 1824， however， WShler reported<br >the preparation of the ammonium salt of oxalic acid by passing<br >cyanogen into ammonia water， and in 1828 he reported the prepara-<br >tion of the organic compound urea by heating the inorgamc com-<br >pound ammonium cyanate: NI-I4OCN + heat ---* H2N.CO.NHs.<br >This experimental work led to the development of the concept<br >that animate processes are not essential for the formation of<br >organic compounds.<br >Importance of Organic Chemistry，<br > Organic chemistry is involved in practically every activity of<br >modern life. Anesthetics， anti-freezes， clothing， disinfectants，<br >drugs， dyes， explosives， fertilizers， films， flavors， food， fuel， paints，<br >perfumes， p .astics， resins， rubber， and numerous other essential<br >commodities are studied， analyzed， and synthesized with the aid<br >of the basic principles of organic chemistry.<br >Number of Compounds:<br > More than a quarter of a million organic compounds are known.<br >They out-number all other chemical compounds in the ratio of<br >about ten to one.<br >Phenomenal Capacity of Carbon:<br > The existence of this large number of organic compounds is due<br >to the unique capacity of carbon atoms to unite to form chains or<br >rings of more or less complexity. A simple illustration is afforded<br >~y the following series of compounds which are known as the<br >saturated hydrocarbons:<br >