138 



MR J. Y. BUCHANAN ON THE 



be performed on an equivalent solution of RbClOg, the decrease is — 0'126 Gx ; if the 

 salt in solution be CsClOg, the decrease is — 0'158 Gj. Therefore, when we replace 

 the chlorine by bromine in 1/16 grm.-mol. solutions of the chlorates of K, Rb, and Cs 

 we observe that the change produces a decrease in the displacement of the solution, 

 and this decrease becomes greater as the atomic weight of the metal increases. 



Confining our attention next to the changes produced in the displacement by- 

 varying the metal combined with the same acid, we find that when K is replaced by 

 Rb in KCIO3 the displacement of the solution increases, as it also does when Rb is 

 replaced by Cs in RbClOg. There is a similar increase when we consider the bromates 

 of the same three metals ; but replacing K by Rb in KBrOg produces a smaller increase 

 than when the same change is made in KCIO3. Similarly, the replacement of Rb by 

 Cs in RbBr03 is less than when Cs replaces Rb in RbClOg. In the four cases where 

 an exchange of metals takes place the corresponding changes in the displacements are 

 positive ; with the three changes obtained by replacing CI by Br the changes in the 

 displacement are negative, and numerically less than when the metals are changed. 



K. 



Diflf. 



Rb. 



DiflF. 



BrOg 

 I0„ 



2-761+0-296 

 2-189 + 0-387 



Diff. - 0-572 



3-057 + 0-454 

 2-576 + 0-327 



0-481 



Cs. 



V. 



= 3-511 

 = 2-903 



-0-608 



With the bromates and iodates of the same three metals we find that replacing the 

 bromine by iodine causes a reduction in the displacement of — 0*572 Gx in tbe case of 

 KBrOg ; with RbBrOg the change in the displacement is — 0'481 G^ ; and with CsBrOg 

 it is — 0'608 Gx- When we compare the results obtained by changing the metal 

 combined with the same acid, we find that the iodates have positive values for the 

 change in the displacement, just as the bromates and chlorates had, but that, whereas 

 the replacement of Rb by Cs in RbClOg and RbBrOg gave an increase in the displace- 

 ment which was greater than that produced by the exchange of Rb for K in KCIO3 and 

 KBrOg, the replacement of Rb by Cs in RblOg causes an increase in the displacement 

 which is less than that caused by replacing K by Rb in KlOg. The results of the 

 changes produced in the displacement by the replacement of one constituent by 





K. 



Diff. 



Rb. 



Diff. 



Cs. 



Diff. 

 (K by Cs). 



C103 



Diff. 



BrOs 

 Diff. 



IO3 

 DiffClOgbylOg 



-0-024 



0-398 



-0-126 



0-486 



-0-158 



0-884 



-0-572 



0-296 



-0-481 



0-454 



-0-608 



0-750 



-0-596 



0-387 



-0-607 



0-327 



-0-766 



0-714 















