;;i-_> 



Van Name and Hill — Solution of Metals 



wholly free from the black coating formed in some eases in 

 the sulphate solution. As before, the expression C-fl — f(c-c ) 

 was used in calculating the velocity constants for iron. 



Copper dissolving in an acidified ferric chloride solution is 

 oxidized in two stages, the case being therefore unlike that of 

 copper in ferric sulphate, but closely analogous to that of tin 

 in ferric sulphate. As in the latter case, the titer of the solution 

 toward permanganate is not changed by the second stage of the 

 oxidation, so that the analyses do not distinguish between ferric 







Table VII. 















FeCl 3 



, 0-05 mola 



r. 





i 





No. of 

 Exp. 



HC1, 0-5 molar. 



Cadmium. 









K 



1. k = 



4-17 4-OS 



4-16 



4-16 



4 13 



418 



4-20 



415 



2. k = 



4-09 4-28 

 HC1, 0-1 molar. 



415 



427 



4-21 



4-18 



4-12 



419 



3. k = 



432 4-16 



4-37 



4-12 



4-14 



4-25 



4-29 



424 



4. k = 



4-12 4-15 

 IIC1, 0'5 molar. 



417 



4-18 

 Iron. 



412 



4-14 



4-12 



414 



5. k = 



426 4-30 



4 29 



415 



439 



4.50 



441 



433 



6. ft = 



424 434 

 HC1, 01 molar. 



4-39 



437 



4-40 



4-40 



444 



437 



7. k = 



418 4-10 



4-18 



435 



4-18 



3-83 



422 



415 



8. k = 



4-0S 411 

 HC1, 0-5 molar. 



4 06 



4-12 

 Copper. 



4'17 



4-16 



4 15 



4-12 



9. ft = 



4-26 4-22 



4-32 



442 



4-33 



4-49 



441 



435 



10. k = 



4'14 4-25 

 HC1, 01 molar. 



4-29 



437 



4-28 



422 ■ 



4-20 



425 



11. k = 



3 43 3 28 



3-26 



3-17 



3-16 



3-09 



2-99 



3-20 



12. k = 



356 332 



3-30 



3 23 



315 



302 



3-11 



324 



Initial velocities by extrapolation : Exp. 9, 4 - 2C 



1; Exp. 



10,4-20; 



Exp. 11, 



3-40; 



Exp. 12, 3-48. 



chloride and cupric chloride, but give their sum. The velocity 

 constants have been calculated in exactly the same way as in 

 the tin experiments. In fact, the sole difference between the two 

 cases is that here the second stage of the reaction is compara- 

 tively rapid. A good deal of cupric chloride must therefore 

 have accumulated in the solutions, reaching, at the close of 

 Experiments 9 and 10, in which this effect was largest, a con- 

 centration considerably larger than that of the ferric chloride 

 itself. 



