1074 
in which the velocity of the reaction is proportional to the amount 
of chloride present and to the quantity of the catalyst. 
In that case, at a given concentration of the catalyst, a change 
of the initial concentration of the acid chloride should not cause 
any modification in the value of the constant. 
If, however, we take an excess of acid chloride we obtain the 
following : 
fT ABLE-Y: 
Concentration AlCl3 = 0.1 n.; acid chloride = 0.15 n.; t= 30°. 
t 2/3 XK (a—x)108 Ky} Ky 
0 90.8 — — 
120 83.9 0.000656 0.00106 
240 11.5 | 0.000662 0.001 10 
360 12.5 | 0.000617 0.00105 
TABLE VI. 
Concentration AlCl3 = 0.1 n.; acid chloride = 0.2 n ; f= 30°. 
t Ip XK (a—x1) 108 Ky Ky 
ee 89.7 0 = 
185 | 82.0 0.00487 0.00117 
370 16.6 0.00427 0.00108 
585 | 70.9 0.00402 0.00110 
Herein K, has been calculated as if all the acid chloride present 
is concerned in the reaction, hence in accordance with the above 
schema, whereas A’, has been calculated as if only the acid chloride 
which has formed a molecular compound with the AICI,, enters 
into reaction. 
It is easy to see that, only on the latter supposition, we obtain a 
eonstant without course and which agrees with the constant obtained 
with equimolecular quantities of acidchloride- AlCl, (concentration N/). 
The excess of acidehloride is therefore quite inactive; only that 
acidehloride whieh is combined with the aluminiumehloride is active. 
Hence in connection with the preceding, applies the relation : 
