Phosgene (CC1₂O) is a colorless gas that was used as an agent of chemical warfare in World War I. It has the odor of newly mown hay (which is a good warning if you know the smell of newly mown hay). Pete Brouillette an innovative chemical engineering student came up with what he believed was an effective new process that utilized phosgene as a starting material. He immediately set up a reactor and a system for analyzing the reaction mixture with a gas chromatograph. To calibrate the chromatograph (i.e., to determine its response to a known quantity of phosgene), he evacuated a 15.0 cm length of tubing with an outside diameter of 0.635 cm and a wall thickness of 0.559 mm, and then connected the tube to the outlet valve of a cylinder containing pure phosgene. The idea was to crack the valve, fill the tube with phosgene, close the valve, feed the tube contents into the chromatograph, and observe the instrument response. What Pete hadn’t thought about (among other things) was that the phosgene was stored in the cylinder at a pressure high enough for it to be a Liquid. When he opened the cylinder valve, the liquid rapidly flowed into the tube and filled it. Now he was stuck with a tube full of liquid phosgene at a pressure the tube was not designed to support. Within a minute he was reminded of a tractor ride his father had once given him through a hayfield, and he knew that the phosgene was leaking. He quickly ran out of the lab, called campus security, and told them that a toxic leak had occurred and that the building had to be evacuated and the tube removed and disposed. Personnel in air masks shortly appeared, took care of the problem, and then began an investigation that is still continuing.

(a) Show why one of the reasons phosgene was an effective weapon is that it would collect in low spots soldiers often entered for protection.

(b) Pete’s intention was to let the tube equilibrate at room temperature (23°C) and atmospheric pressure. How many gram-moles of phosgene would have been contained in the sample fed to the chromatograph if his plan had worked?

(c) The laboratory in which Pete was working had a volume of 2200 ft³, the specific gravity of liquid phosgene is 1.37, and Pete had read somewhere that the maximum “safe” concentration of phosgene in air is 0.1 ppm (0.1 X 10^-6 mol CCl₂O/mol air). Would the “safe” concentration have been exceeded if all the liquid phosgene in the tube had leaked into the room and evaporated? Even if the limit would not have been exceeded, give several reasons why the lab would still have been unsafe.

(d) List several things Pete did (or failed to do) that made his experiment unnecessarily hazardous.