Chemical reactions involve interaction of atoms and molecules.A large number of atoms/molecules are present in a few grams of any chemical compound varying with their atomic/molecular masses.To handle such large numbers conveniently,the mole concept was introduced.This concept has implications in diverse areas such as analytical chemistry,biochemistry,electrochemistry and radiochemistry.The following example illustrates a typical case involving chemical/electrochemical reaction.A H.O molar aqueous solution of NaCl is prepared and 500ml of this solution is electrolysed.This leads to the evolution of chlorine gas at one of the electrodes(atomic mass:Na=23,Hg=200;1 faraday=96500 coulombs).The total number of moles of chlorine gas evolved is:
