160 G. S. Jamieson — Determination of Lead as Sulphite. 



*0. 



Pb taken 



Zn taken 



Pb found 



Error 



1 



2 



•1183 

 •1174 



•1791 



•1194 



•1187 

 •1170 



+ •0004 

 — •0004 



These two experiments would indicate that lead can be sepa- 

 rated by means of sodium bisulphite without special precau- 

 tions from those metals (except the alkali earth metals) which 

 are not reduced by the sulphite. 



It will be observed that this method could be applied with 

 advantage to the precipitation of lead from solutions contain- 

 ing acids other than sulphuric, because, as shown above, it is 

 only necessary to nearly neutralize the acid with ammonia 

 instead of removing it by evaporation with sulphuric acid, 

 which is the usual procedure with the sulphate method. 



Several attempts were made to titrate lead sulphite with 

 potassium iodate in the presence of strong hydrochloric acid, 

 but as the results obtained were always somewhat low, it was 

 found preferable to weigh the precipitate. 



Sheffield Chemical Laboratory, Yale University, 

 May 20, 1915. 



