Determinants of solubility:\nWhich factor typically has the least effect on the solubility of a solute in a liquid solvent (excluding gases)?

Introduction / Context:
For liquid solutions (and most solid–liquid systems), solubility trends are governed primarily by molecular interactions and temperature. Pressure has only a minor influence at ordinary conditions, unlike in gas–liquid systems where Henry’s law leads to strong pressure dependence.

Given Data / Assumptions:

• We exclude gas solubility, which is highly pressure dependent.
• Ambient to moderate pressures typical of laboratory and industrial operations.
• No chemical reaction between solute and solvent.

Concept / Approach:
“Like dissolves like” captures the dominant role of solute–solvent interactions. Temperature affects solubility via enthalpy/entropy of dissolution. Pressure changes liquid molar volumes only slightly, so the effect on chemical potentials and hence solubility is minimal for condensed phases.

Step-by-Step Solution:
Rank influences qualitatively: identity of solute/solvent > temperature ≫ pressure.Recognize liquids and solids are nearly incompressible: small dμ/dP.Therefore, pressure usually has the least impact on solubility (non-gaseous systems).

Verification / Alternative check:
Data compilations show modest solubility shifts with large pressure changes for liquids/solids, in contrast to the near-linear pressure effect for gases.

Why Other Options Are Wrong:
Nature of solute/solvent strongly determines compatibility. Temperature frequently changes solubility by large factors. Trace salts can “salt in” or “salt out,” sometimes noticeably; still generally larger than pressure effects.

Common Pitfalls:
Overgeneralizing Henry’s law (gases) to liquid/solid solubility problems.

Final Answer:
Pressure of the system