Hydrogen chloride gas, HCl(g), with a gas-phase dipole moment of 1.08 D, is introduced separately into three sealed bulbs that each contain 1.0 mol of a different noble gas at 25 °C and 1 atm.
The polarizabilities (α) of the noble gases are given.
• He: 0.20 ų • Ar: 1.64 ų • Xe: 4.04 ų
Assume ideal-gas behavior and negligible volume change upon mixing.
(a) Rank the three HCl–noble-gas mixtures in order of expected magnitude of attractive intermolecular interaction between HCl and the noble gas. Clearly state the strongest and weakest mixtures and support your ranking.
(b) Experimental calorimetry shows that the enthalpy change on mixing HCl with Ar is −2.0 kJ mol⁻¹ (at the stated conditions). Using proportional reasoning based on the data provided, estimate the corresponding enthalpy change for the HCl–Xe mixture. Show your reasoning.
(c) State one experimental consequence (other than enthalpy change) that would differ among the three mixtures as a result of the trend you predicted in part (a), and explain why that consequence follows from the differing intermolecular attractions.