142 
IOWA ACADEMY OB^ SCIENCE 
This is strikingly different from results obtained by Burke and Donnan 
(loc. cit.) with mixtures of ethyl alcohol and water in which they found a 
maximum near the alcohol end of the velocity coefficient — solvent curve. It is 
doubtful if one is justified in considering the mean values of these velocity 
coefficients, but they will be used to bring out more clearly some general 
relations. 
A variation from the law of averages is shown by a slight sagging of the curve 
when the mean constants for any one series is plotted against solvents. 
By plotting the coefiSicients for each solvent in a series against time as 
abscissae, it will be seen that curves for the mixed solvents are drawn towards 
that in pure ethyl alcohol, thus showing the dominating influence of the latter 
solvent. 
Table II shows the results of a series of experiments similar to those of Table I 
except that non-equivalent solutions were used, and the same general relations 
apply here. A comparison of these tables shows that with the same initial con- 
centration of silver nitrate, the velocity coefficients increase as the initial con- 
centration of the ethyl iodide decreases. 
TABLE II.— VELOCITY COEFFICIENTS. 0.025N AgNOs AND 0.0125N C 2 H 5 I 
IN ALCOHOLS AS SOLVENTS. 
100 % 
Ethyl Alcohol 
75% Ethyl Alcohol 
25% Methyl Alcohol 
50% • Methyl Alcohol 
50% Ethyl Alcohol 
t 
c 
t 
c 
t 
c 
0 
10. 
0 
10. 
0 
10. 
10 
8.445 
''?0040r~ 
5 
8.90 
.00528 
5 
8.78 
.00598 
21 
7.29 
.00443 
10.5 
8.145 
.00492 
10.5 
8.07 
.00521 
36 
6.875 
.00337 
15 
7.70 
.00473 
15 
7.43 
.00566 
55 
6.045 
.00386 
20 
7.32 
.00458 
20 
7.055 
.00540 
75 
5.71 
.00371 
20 
6.94 
.00447 
26 
6.645 
.00541 
130 
5.285 
.00343 
33 
6.65 
.00425 
33 
6.255 
.00542 
200 
5.06 
.00374 
40 
6.296 
.00444 
40 
6.10 
.00510 
60 
6.06 
.00423 
50 
5.84 
.00498 
25% Ethyl Alcohol 
75% Methyl Alcohol 
100% Methyl Alcohol 
t 
c 
l£ 
t 
c 
•fc 
0 
10. 
5 
8.46 
.00804 
0 
10. 
10.5 
7.59' 
.00728 
5 
S.345 
.00884 
15 
7.03 
.00732 
10 
7.355 
.00891 
20 
6.63 
.00710 
18 
6.51 
.00853 
26 
6.30 
.00681 
25 
6.075 
.00831 
33 
6.005 
.00666 
32 
5.82 
.00792 
40 
5.83 
.00628 
35 
5.70 
.00802 
60 
5.615 
.00607 
43 
5.495 
.00797 
A much greater difference may be observed in the values of the velocity co- 
efficients in Tables II and III, than was just seen in a comparison of Tables 
I and II. 
