253 
To begin with, in the first series of his experiments, which are 
meant to prove that the diazotisation reaction is bimolecular, he 
uses a nitrite solution containing 0,20 gr. in 1 L., that is a 0.0029 
normal solution, whereas theoretically (assuming the nitrite to be 
100 °/,) it should have been 0.0025 normal. This is too high by 
about 13°/,. As even the technically pure nitrite is 96 °/,, he always 
works with an excess of the nitrite in respect to the amine. Espe- 
cially his last determinations will therefore become erroneous. 
Casually we may point out that he finds after integration of 
ae = K (a—x)’ that: A= 5 : Elie 
dt ; t 100—2 
2 v 
100 ¢°100—z" 
while of course this ought to be K= So he finds 
K a hundred times too great. 
Further his determinations do not make the impression of being 
very accurate. He can read his spectrophotometer only to */, scale 
division. For the different amines a half scale division however can 
cause great divergences when we calculate in percentages. As appears 
from the table below, this may give rise to errors from 1'/,—11°/,. 
for aniline are |, 
i. p. toluidine cla) ee 
‘ 0. . lande 
sf m. xylidine Jeje 
x 0. anisidine See's 
Ë p- » Dele le 
»  p. nitraniline 3'/, °/ 
0. ‘i LO 
5 m. 55 HE naj 
The reaction constant of the diazotisation is calculated by Tassrr.ry 
‚rather arbitrarily. For instance for p-toluidine he derives it from a 
determination made after 45 minutes, however if considerably deviates 
from the K’s which we calculated from his determinations relating 
to other periods. If he had taken the average K, the agreement 
between the found percentage of inverted amine and the one cal- 
culated, would have been much better. 
He was more fortunate for p-anisidine. He found 0.142 for K 
after 30 minutes, while the average of the first four determinations 
gives K = 0.143. (See page 254). 
7 
