dilute solution in which the solute may be regarded as obeying Henry's law, so that all the solute activity coefficients may be approximated to 1.
Physical Chemistry Division, unpublished
PAC, 1994, 66, 533. 'Standard quantities in chemical thermodynamics. Fugacities, activities and equilibrium constants for pure and mixed phases (IUPAC Recommendations 1994)' on page 545 (https://doi.org/10.1351/pac199466030533)