OF ARTS AND SCIENCES. 



191 



Corrected Error of Insoluble Chloride 

 precipitated precipitated precipitated 



No. 

 Exp. 



Chloride. 



NaCl 



once from 



about 13 



gnn. of 



LiCl. 



gnn. 

 0.0006+ 



0006+ 



,0002+ 

 0010+ 



once from 



about 0.013 



grm. of 



LiCl. 



grm. 



twice fi-oui 



about 0.13 



grm. of 



LiCl. 



grm. 



0.0000 



0.0005— 

 0.0004— 

 0.0000 

 0.0007+ 



Error in 



corrected 



Weight of 



LiCl. 



grm. 



0.0002— ■ 

 0.0002— 

 0.0008— 

 0.0010—, 



Approximate 



Mean Error 



of LiCl. 



grm. 



0.0005- 



0.0003+ 

 0.0007— 

 0.0003— 

 0.0007— 

 0.0002— 

 0.0003— 



grm. 



0.0007— ^ 



0.0006+ / 

 0.0003+ f -0003+ 

 0.0011+) 



(23) 



(24) « 



(26) KCl 



(27) « 



(25) NaCl 



(28) KCl 



(29) " 



(30) NaCl+KCl 



(31) " 



(32) NaCl 



(33) « 



(34) KCl 



(35) " 



(36) " 



(37) " 

 Approx. mean, 0.0006+ 0.00004— 0.0003— 



Few processes in analytical chemistry are capable of yielding results 

 more exact than these. The separation of from 0.1 grm. to 0.2 grm. 

 of sodium or potassium chloride from a tenth of its own weight of 

 lithium chloride is practically perfect in one operation, and from its 

 own weight of lithium chloride the parting may be effected satisfac- 

 torily by two precipitations. 



The points to be observed in executing the method may be recapitu- 

 lated as follows : — 



To the concentrated solution of the chlorides, amyl alcohol is added 

 and heat is applied, gently at first to avoid danger of bumping, until, 

 the water disappearing from solution and the point of ebullition rising 

 and becoming constant for some minutes at a temperature which is 

 Hpproximately that at which the alcohol boils by itself, the chlorides 

 of sodium and potassium are deposited and lithium chloride is dehy- 

 drated and taken into solution. At this stage in the operation the 

 liquid is cooled and a drop or two of strong hydrochloric acid added to 

 reconvert traces of lithium hydrate in the deposit, and the boiling 

 continued until the alcohol is again free from water. If the amount 

 of lithium chloride present is small it will now be found in solution, 

 and the chlorides of sodium and potassium will be in the residue, 



