Consider steady state mass transfer of a solute $A$ from a gas phase to a liquid phase. The gas phase bilk and interface mole fractions are $y_{A,G}$ and $y_{A,i}$, respectively. The liquid phase bulk and interface mole fraction are $x_{A,L}$ and $x_{A,t}$, respectively. The ratio $\frac{\left ( x_{A,i}-x_{A,L} \right )}{\left ( y_{A,G}-y_{A.t} \right )}$ is very close to zero.
This implies that mass transfer resistance is
- negligible in the gas phase only
- negligible in the liquid phase only
- negligible in both the phases
- considerable in both the phases