592 Mr Lamplough, On the determination of the rate of 
The solution was then vigorously stirred whilst the reaction 
vessel was in contact with the air, and after about 15 seconds the 
three-way tap was turned so as to connect the vessel with the 
burette, and the evolution of gas was measured. 
In the following table are given the readings and calculated 
values for the constant in the case of an experiment performed at 
72° C., the law of a unimolecular reaction being assumed for the 
calculation of the constant. 
Decomposition of Formic Acid by Sulphuric Acid. 
Sodium formate N / 2 solution 5 c.c. Temperature 72°. 
Sulphuric acid, pure, N/2 solution 20 c.c. 
Gas evolved, c.c. 
Time, minutes 
Constant K 
(calculated for uni- 
molecular action) 
0-3 
0-00 
8 
0-83 
•0635 
12 
1-28 
•0647 
20 
2-28 
•0659 
28 
3-85 
•0649 
36 
5-07 
•0650 
45 
7-38 
•0642 
53 
10-36 
•0640 
59 
13-99 
•0639 
65 
22-09 
•0640 
66-8 
29-79 
•0646 
End-point from curve 67‘6 c.c. 
Mean value of constant ‘0645. 
A second experiment, performed at 73°‘8C. with equally good 
results, gave a value of '0770 for the constant ; the composition of 
the reaction mixture remained unchanged. 
The results of these experiments show that the decomposition 
of formic acid by sulphuric acid is a true unimolecular reaction. 
Hence it follows that the action is simply the one represented 
by the equation : 
HCOOH = H 2 0 + CO, 
and not some such action as 
HCOOH + HCOOH - (HC0) 2 0 + H 2 0 
followed by the rapid reaction : 
(HC0). 2 0 = HoO + 2 CO, 
