Raoult’s law prerequisites: Raoult’s law states that the equilibrium vapor pressure exerted by a component in a solution is proportional to its mole fraction in the liquid phase. This generalization assumes which of the following about the solution and its components?

Introduction / Context:
Raoult’s law underpins many introductory vapor–liquid equilibrium (VLE) treatments. It works best for ideal or nearly ideal solutions—typically those with similar molecular sizes and intermolecular forces—so that deviations from ideality are small.

Given Data / Assumptions:

• Binary or multicomponent liquid solutions in equilibrium with their vapor.
• No chemical reaction or association between unlike molecules.
• Non-polar or weakly polar species of comparable size.

Concept / Approach:
Raoult’s law states p_i = x_i * p_i^sat. This relation follows from the ideal-solution model, which assumes the partial molar properties mirror those of the pure liquids at the same temperature. Ideal-solution behavior is expected when molecular interactions between like and unlike species are similar, and when molecules have comparable sizes and shapes. Strong polarity, hydrogen bonding, or specific association leads to nonideal behavior and the need for activity coefficients.

Step-by-Step Solution:
Identify conditions for ideality: similar size, similar interaction strength, and absence of complexation or association.Match with options: (a), (b), and (c) each reflect these conditions.Therefore, all three are required for the best applicability of Raoult’s law.

Verification / Alternative check:
Mixing chemically similar hydrocarbons (e.g., hexane–heptane) typically obeys Raoult’s law closely. In contrast, polar–nonpolar mixtures (e.g., ethanol–hexane) show large deviations and require activity-coefficient models.

Why Other Options Are Wrong:
Selecting only one or two assumptions ignores the others that also materially affect ideality.

Common Pitfalls:
Assuming Raoult’s law applies to strongly associating systems; forgetting that activity coefficients (γ_i) correct for nonideality: p_i = x_i * γ_i * p_i^sat.

Final Answer:
All of (a), (b), and (c).