The gas phase decomposition of phosphine at 120 °C PH3(g)- →1/4 P4(g) + 3/2 H2(g) is first order in PH3. During one experiment it was found that when the initial concentration of PH3 was 6.02×10-2 M,...

Extracted text: The gas phase decomposition of phosphine at 120 °C PH3(g)- →1/4 P4(g) + 3/2 H2(g) is first order in PH3. During one experiment it was found that when the initial concentration of PH3 was 6.02×10-2 M, the concentration of PH3 dropped to 8.61×10-3 M after 80 s had passed. Based on this experiment, the rate constant for the reaction is