The Thermal Decomposition of Acetaldehyde, CH₃CHO $\rarr$ CH₄ + CO, Is a Second-Order Reaction

The thermal decomposition of acetaldehyde, CH₃CHO $\rarr$ CH₄ + CO, is a second-order reaction. The following data were obtained at 518 ^$\circ$ C. $\begin{array}{cc}\text { Time, } \mathrm{s} & \text { Pressure } \mathrm{CH}_{3} \mathrm{CHO}, \mathrm{mmHg} \\\hline0 & 364 \\42 & 330 \\105 & 290 \\720 & 132\end{array}$ Calculate the rate constant for the decomposition of acetaldehyde from the above data.

A) 2.2 * 10^-3/s
B) 0.70 mmHg/s
C) 2.2 * 10^-3/mmHg·s
D) 6.7 *10^-6/mmHg·s
E) 5.2 * 10^-5/mmHg·s