304 Van Name and Hill — Solution of Metals 



was 5 molar were made with ammonium ferric alum, after 

 special tests had shown that the two alums gave practically 

 identical results. 



Cadmium. — Experiments with metallic cadmium (Kahl- 

 banro's) are recorded in Table I. Here, and in all the follow- 

 ing tables, /,•, is the observed velocity constant, uncorrected, 

 /■ is the same corrected for variations in the rate of stirring, 

 and K the averaged value of k for the single experiment. By 

 way of illustration, data for Experiment 1 are given in full. 

 For the rest only the corrected velocity constants are recorded. 



Table I. • 



Metal: Cadmium. R'FeCSO^ , 0*05 molar. 



h\ = velocity constant as observed, uncorrected. /.■ = constant corrected 





for variations in 

 experiment. 



the rate of stirring. K = 



average 



constant for the single 



No. oi 

 Exp. 



1. 



V — 



At= 

 c = 

 h = 



k = 



C 



0'4 



= 50-00 



580 



7 



7 2 



396 



3 94 



560 



6 



78 4 



3-93 



393 



H a SO-4 , 



540 



6 



73 6 



4-04 



4-01 



O'Ol molar. 



520 500 480 



6 6 6 



72 8-72 10-69 12 



4-11 4-06 4-18 



4-11 4-09 4-14 



460 



6 



69 14-61 



4-04 



4 02 



K 

 403 



2. 



/.• = 





4-01 



3-99 



4-01 



3 93 



3-92 



4-10 



4-04 



400 



3. 



/: = 





4-01 



4-01 



405 



4'22 



4-29 



4-12 



4-29 



414 



4. 



k = 





3 98 



3-98 



4-08 



4-12 



4-09 



4-02 



4-06 



405 



5. 



fc = 





4-13 



4-00 



423 



4-34 



4-48 



4-20 



4-39 



425 



6. 



A- = 





4 '00 



3-98 



4-20 



4-33 



4'50 



4-34 



4-22 



4-22 













HsSOi , 



0'25 molar. 









7. 



/.• = 





4-14 



4-10 



4-25 



4-20 



4-19 



4-25 



4-09 



417 



8. 



k = 





4-18 



4-04 



3-97 



4-19 



4-21 



4-20 



4-12 



413 













H2SO4 j 



l - 25 molar. 









9. 



h = 





3-48 



3-46 



3 53 



3-56 



3'61 



3-58 



3-61 



355 



10. 



h = 





3 46 



3-47 



3-51 

 H a S0 4 



3-60 

 , 5 mol 



3-62 

 ar. 



3-53 



3-51 



353 



11. 



k = 





1-78 



1-76 



1-75 



1-84 



1-68 



1-78 



1-68 



175 



12. 



k = 





1-75 



1-76 



174 



1-75 



1-79 



1-80 



1-81 



177 



Although it might be expected that an increase in acidity 

 would raise the reaction velocity, it is seen in the table that 

 precisely the reverse is true, at least for concentrations of sul- 

 phuric acid above 25 molar. This effect will be observed in 

 all cases where free sulphuric acid is present, whether the oxi- 

 dizing agent be ferric salt or chromic acid. 



