Chapter 19, Problem 19.134QP

At a certain elevated temperature, ammonia decomposes on the surface of tungsten metal as follows:

${\mathrm{NH}}_3\to \frac{\text{1}}{\text{2}}{\text{N}}_{\text{2}}\text{+}\frac{\text{3}}{\text{2}}{\text{H}}_{\text{2}}$

The kinetic data arc expressed as the variation of the half-life with the initial pressure of NH₃.

(a) Determine the order of the reaction, (b) How does the order depend on the initial pressure? (c) How does the mechanism of the reaction vary with pressure? (Hint: You need to use the equation in Problem 19.129 and plot log t_1/2 versus log P.)