Q4. HD (Bis(2-chloroethyl)sulfide) is sulfur mustard. Its melting point is 13.5°C, too high forcold weather operations. T (O-mustard) is (Bis-(2-chloroethylthioethyl)-ether), a related vesicantcompound with similar structure to HD having lower volatility and similar vesicantcharacteristics. HT is mixture of 60% HD and 40% T by mass, having a depressed melting point.HT is a clear, yellowish, highly viscous liquid having many properties similar to HD. It has agarlic-like odor similar to HD. HT is used as a delayed-casualty agent, the persistency of whichdepends on the munitions used and the weather. It has a longer duration of effectiveness, and hasa lower melting temperature than HD. (30 Points) HD: Cl CH₂CH₂ S CH₂CH₂ClT: (Cl CH₂CH₂ S CH₂CH₂)₂O(O-mustard) Explain the relative volatility of T compared to HD in terms of molecular structure andintra-molecular forces. The vapor pressure of HD is 0.082 torr at 22C and 0.1059 torr at25C. The vapor pressure of T is 3x10³ torr at 25C. Do a calculation to estimate the vaporpressure of HT at 25C. Pr = XAP°s + XBP°B Where POA and Pºв are vapor pressure of the two components of the mixture while XA and XB arethe mole fractions (xª + x³ =1; respective mole fractions (xÅ and XÂ) should be calculated by theirrelative mass divided by their molecular weight. Molecular Weight of HD: 159.07; MolecularWeight of T: 263.2)

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