Interphase mass transfer fundamentals: The rate of mass transfer between two contacting fluid phases does not necessarily depend on which of the following characteristics?

Introduction / Context:
Mass transfer across liquid–gas or liquid–liquid interfaces is central to absorption, stripping, extraction, and aeration. The overall rate depends on transport resistances and interfacial driving forces, but not all listed factors are essential in the absence of reaction.

Given Data / Assumptions:

• No chemical reaction at the interface or in the phases (pure physical mass transfer).
• Binary or dilute multicomponent systems.
• Isothermal operation.

Concept / Approach:
For physical mass transfer, the key determinants are: (1) physical properties (diffusivity, viscosity, density) that set film coefficients; (2) hydrodynamics or turbulence that thin boundary layers; and (3) interfacial area, which multiplies the local flux. Chemical properties matter primarily when reaction modifies the effective driving force or introduces enhancement factors.

Step-by-Step Solution:
Write an overall rate form: N = K_overall * A * ΔC (or Δp).Recognize K_overall depends on physical properties and turbulence (film theory).A is the interfacial area created by dispersion/packing.Without reaction, specific chemical reactivity does not directly set the rate.

Verification / Alternative check:
In gas absorption of a sparingly soluble gas without reaction, altering viscosity, diffusivity, or agitation changes rates, while changing “chemical nature” without affecting solubility/physical parameters has little effect.

Why Other Options Are Wrong:
Physical properties determine film coefficients and solubility.

Turbulence reduces film thickness and increases transfer coefficients.

Interfacial area directly scales the total transfer rate.

Common Pitfalls:

• Confusing chemical equilibrium (which sets driving force) with intrinsic chemical reactivity; here no reaction is considered.
• Neglecting that reactions can dramatically enhance transfer—an exception noted but not part of this basic case.

Final Answer:
Chemical properties of the phases