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Show 1.6.6 it is necessary for A* to be about 2 or larger. The plot of y as a function of A' simply is a straight line between the points (0,A) and (A,0). III. COMPARISON WITH EXPERIMENT The results of Sec. II can be compared with the experimental data presented in [41 This requires knowledge of k3[0H] and [N0]c as a function of temperature. Representing k3COH3 by the empirical expression k3[OH3 = C1exp<C2/T) <16> and noting that [N03c = [Ciexp(C2/T)3/(kik3/k2), it follows that there are three adjustable parameters: C^, C2 and k^k3/k2. These parameters can be determined by a curve-fitting procedure, using some of the data shown in Fig. 2 of [43. The latter data are reproduced in the present Fig. 3. They represent measured values of [N03 at the end of the test section of a combustion tunnel as function of temperature T, for various values of A = [NH330/[N030. At constant A the results show a pronounced minimum near T si 1230 K (s; 1755 °F). At temperatures below this minimum, there is insufficient time available for reactions (l)-(3) to be completed. As a consequence, the result for [NO] at these temperatures depends strongly on k3COH3, and only weakly on [N03c. Conversely, at temperatures above 1230 K the final value of [N03 depends strongly on [N03c, and only weakly on k3[0H3. The curve-fitting procedure followed made use of this by determining the value of k3[OH3 at a low temperature (1076 K), and the value of [N03c at a high temperature (1287 K). This allowed expressing Ci and C2 in terms of k^k3/k2. The value of the latter parameter then was determined by trial and error. The criterion used was the closeness of fit between calculated results and the experimental data with A • 1.6 near the minimum in Fig. 3. Use was made of the linear relation between test section residence time tr and temperature T indicated in [41* The procedure followed yielded the values k1k3/k2 • 2.2 x 1010 cm3gmole_1s"1 (17) k3[OH3 = 0.035 s"1, [N03c = 0.14 ppm at T = 1076 K (18) k3COH] = 12.0 s"1, [NO]c « 57 ppm at T = 1287 K (19) Using the values obtained for k3[OH] and [NOIQ, complete results were evaluated for NO as a function of T at conditions corresponding to those of Fig. 2 of [4]. The results are given by the curves of the present Fig. 3. It can be seen that the fit to the set of experimental data is satisfactory, especially to those with A = 1.6 and A - 1.1. For decreasing values of A the experimental data show a downward shift of the optimum temperature for |