IOWA ACADEMY OF SCIENCE 
141 
One minute is the unit of time. The unit of volume is one cubic centimeter. 
The unit of concentration for silver nitrate is the amount of silver nitrate in 
one cubic centimeter of 0.025N solution, e. g., the concentration of ten cubic 
centimeters of an 0.05N silver nitrate solution is twenty. The concentration 
of ethyl iodide is expressed in equivalent terms. Unless otherwise stated, all 
data is the average of duplicate experiments made the same day. 
EXPERIMENTAL. 
Where the reacting substances are present in equivalent amounts, the velocity 
coefficients, k, are calculated according to the usual bimolecular reaction 
formula: fK=T- - ) 
^ A (A-x) • 
where x is the portion of the silver nitrate transformed in time t and A is 
taken as its initial concentration. 
In the case of all non-equivalent solutions the following form of the bimole- 
cular equation was used: (K=^ 
^ (A-D+t A(B-x) 
where the characters have the usual meaning. 
Table I gives the results of duplicate experiments carried out in each of the 
five solvents, using equivalent solutions. For any particular reaction, the 
velocity coefficients show a fairly constant value. However, there is an un- 
mistakable tendency to decrease, especially noticeable as the proportion of 
methyl alcohol increases, and this decrease is very much greater during the 
first part of the reaction. On the other hand, the velocity coefficients become 
larger as the proportion of methyl alcohol increases. 
TABLE I.— VELOCITY COEFFICIENTS. 0.025N AgN03 AND 0.025N C 2 H 5 I 
IN ALCOHOLS AS SOLVENTS. 
100% 
Ethyl Alcohol 
75% Ethyl Alcohol 
25% Methyl Alcohol 
50% Ethyl Alcohol 
50% Methyl Alcohol 
t 
c 
k 
t 
e 
k 
t 
c 
k 
0 
10. 
0 
10. 
0 
10. 
9 
7.495 
.00371 
5 
8.12 
.00463 
5 
7.77 
.00574 
18 
0.055 
.00367 
10 
6.995 
.00430 
■ 10 
6.67 
.00499 
30 
4.97 
.003.37 
15 
6.185 
.00411 
15 
5.73 
.00497 
•50 
3.785 
.00328 
26 
, 4.96 
.00406 
25 
4.63 
.00468 
75 
2.85 
.00334 
40 
3.96 
.00381 
40 
3.64 
.00437 
100 
2.12 
.00338 
55 
3.26 
.00376 
55 
2.965 
.00431 
75 
2.69 
.00362 
75 
2.33 
.00438 
100 
2.305 
.00334 
100 
1.895 
.00427 
Note: c equals concentration of silver nitrate. 
25% Ethyl Alcohol 
75% Methyl Alcohol 
100% Methyl Alcohol 
t 
C 
k 
t 
c 
1 ^ 
if 
10. 
0 
10. 
5 
7.49 
'U00670" 
5 
6.96. 
.00856 
10 
6.15 
.006.26 
10 
5.535 
.00807 
15 
5.145 
.00629 
15 
4.615 
.00778 
25 
4.155 
.00563 
28 
3.385 
.00698 
40 
3.205 
.00530 
51 
2.23 
.00683 ■ 
55 
2.56 
.00528 
70 
1.775 
.00662 
75 
2.08 
.00508 
100 
1.62 
.00517 
