A study of the lead chlorofluoride method for fluoride ion

✍ Scribed by J.H. Saylor; C.H. Deal Jr.; Mary Ellen Larkin; Mary Ellen Tavenner; W.C. Vosburgh

• Publisher: Elsevier Science
• Year: 1951
• Tongue: English
• Weight: 221 KB
• Volume: 5
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)87524-8

✦ Synopsis

In the determination of fluorine in organic compounds in this laboratory the lead chlorofluoride method has usually given results of a lower degree of precision than desired, and a further examination of the method was undertaken.

By the WINKLER method as modified by HOFFMAN AND LUNDELL~ eleven determinations gave a mean of 45.69% F when the gravirnetric procedure was used, and twelve a mean of 46.63% by the volumetric procedure, as compared with the theoretical 45.24%. By the method of KAPFENBERGER* with the chloride determined volumetrically twelve determinations gave a mean of ++.gI%. While the precision was greater than the accuracy in each case, it was not satisfactory.

Analysis of precipitates formed by different methods showed that the composition varied enough in some cases to cause serious errors. Lead chlorofluoride was precipitated by various procedures from solutions containing a known weight of pure sodium fluoride prepared by the method of REYNOLDS AND HILLS.