240 Cc. W. R. POWELL. 
proportional to the amount added, but ceases to have an 
accelerative effect when the amount added is equal to that 
which could have been produced by the potassium par 
manganate originally present in the solution. 
Influence of temperature. 
Temperature coefficients for 10° O. were worked out for — 
solutions containing varying amounts of sulphuric acid. 
The coefficients were obtained by comparing the times 
taken to decompose certain fractions of the total potassium 
permanganate, the velocity constant being considered pro- 
portional to the time. The amount of potassium perman- 
ganate decomposed was plotted against the time the 
reaction had been proceeding, and the time taken for the 
completion of various fractions of the reaction read off from 
the curve thus obtained. 
Table H. 
Acid Temperature. Time taken to decompose. 
concentration. Gh One-tenth. One-eighth. 
-29 N, 5 67 75 
15 21:9 25°5 
ID. ons 5 48:5 53 
15 15 li-p 
LAB ys 5 30°5 33 
15 2D 12 
Table I.—TZemperature coefficients calculated from the figures in 
Table H. 
Acid Temperature coefficients calculated at 
concentration. One-tenth. One-eighth. 
“20 IN. 3°06 2°95 
"DO 55 3°23 3°03 
Loy 3°21 2°75 
The temperature coefficient is about the same at all 
concentrations and is similar to that obtained for most 
chemical reactions. 
