Chemistry. — “Catalysis. X. Explanation of some abnormally large 
and small temperature coefficients’. By Nm Ratan Duar. 
(Communicated by Prof. Ernst COHEN). 
(Communicated at the meeting of September 25, 1920). 
SKRABAL (Monatsh. 1914, 35, 1157) has shown that the velocity 
of formation of iodate from iodine and iodide in a mixture of 
: 8 5 5 ky 10 
sodium carbonate and sodium bicarbonate solutions has —1’° —45. 
it 
When a similar reaction was effected in sodium acetate solution, 
the temperature coefficient is 2. 
The velocity of decomposition of iodate in a mixture of acetic 
bt 
fs : , ky 0 
acid and sodium acetate solution has a Sia a The same reaction 
t 
in a mixture of disodium and monosodium phosphates gives a 
temperature coefficient 1.26; in a mixture of KF and HF, the 
temperature coefficient has the value 0.9 to 1.04 and a mixture of 
sodium sulphate and sodium hydrogen sulphate leads to the value 
of 0.85. 
SKRABAL remarks that the temperature coefficient must necessarily 
undergo a change when the substances, which affect the time 
equation, are transformed into complexes. The relationship between 
the temperature coefficient T of the original reaction and T’, that 
of the reaction between the complex substances is governed by the 
formula, 
oT — e10/RT (T + 10) (MQ) + nQy HH xq1 + Vda Hoer) 
in which Q and q represent the heat changes of the complex 
reaction and the sum (m-+n-+....+x+y-+....) indicates the 
order of the reaction. This formula indicates that a great variability 
of T is to be expected from reactions of the higher orders. 
In a foregoing paper (Annales de Chimie et de physique 1919, 
t. XI, 130) I have definitely proved that this conclusion of SKRABAL, 
which states that the temperature coefficients of polymolecular 
reactions are, in general, greater than those of unimolecular ones, 
is not supported by experimental evidence. 
SKRABAL investigated these two polymolecular reactions: 
31,+60H’=51’+10',+3H,0 and 
10'",+51+6H =31,+ 38,0. 
