An aqueous solution contains Mg²⁺ ions, methanol (CH₃OH), and dimethyl ether (CH₃OCH₃) at equal molal concentrations. Assume the temperature is low enough that the solution remains liquid and that water is the continuous phase.
Consider only the following types of pairwise interactions occurring in the solution:
• Interaction 1: Mg²⁺ with water
• Interaction 2: Methanol with water
• Interaction 3: Dimethyl ether with water
Analyze the relative strengths of these interactions.
(a) Rank Interactions 1–3 from weakest to strongest. Clearly indicate any ties you consider justified.
(b) For each interaction, identify the dominant intermolecular or ion–dipole force involved and explain how the structural features of the interacting species give rise to that force.
(c) Predict which solute (Mg²⁺, methanol, or dimethyl ether) will exhibit the largest deviation from ideal solution behavior (Raoult’s law) with respect to its partial vapor pressure. Provide a justification that integrates your ranking from part (a) with the concept of solvent–solute attractions and volatility.
(d) If the concentration of Mg²⁺ were doubled while the concentrations of methanol and dimethyl ether remained the same, describe qualitatively how the relative magnitudes of the three interactions would change, if at all, and justify your answer.