Reactions of Lead Halides in Molten Potassium Nitrite. Action of Dinitrogen Tetroxide and its Thermal Dissociation Products on Lead Halides. A New Method for Accurate Determination of Iodides in Presence of Chloride and Bromide

Chemistry Department, M. N. College, Visnagar

Manuscript received 3 December 1973; revised 11 October 1974; accepted 20 January 1975

The reactions of lead halides (chloride, bromide and iodide) in molten potassium nitrite has been investigated in highly evacuated all glass system. It has been observed that though nitrogen dioxide, nitric oxide and dinitrogen trioxide are all evolved during the reaction, none of them react with the chloride and bromide salts forming nitrosyl chloride or nitrosyl bromide. In the case of the reaction with iodide too, no nitrosyl iodide is formed; but instead free iodine is knocked out in the elemental state. The reactions have also been carried out in vacuum to study the action of pure dinitrogen tetroxide and its thermal dissociation products on lead chloride, lead bromide and lead iodide. It has been found that no reaction took place on treatment of the tetroxide with the chloride and bromide salts, while quantitative reaction took place with the iodide giving free iodine and not nitrosyl iodide. The ease with which iodine was knocked out from onic iodide by nitrogen dioxide or trioxide suggested an interesting method to est!mate iodine of ionic iodide by meats of nitrogen dioxide dissolved in origanic solvent.