Editing Activity coefficient (section)

== Experimental determination of activity coefficients ==
Activity coefficients may be determined experimentally by making measurements on non-ideal mixtures. Use may be made of [[Raoult's law]] or [[Henry's law]] to provide a value for an ideal mixture against which the experimental value may be compared to obtain the activity coefficient. Other [[colligative]] properties, such as [[osmotic pressure]] may also be used.

=== Radiochemical methods ===
Activity coefficients can be determined by [[radiochemistry|radiochemical]] methods.<ref>{{cite journal|title=Radiochemical Measurements of Activity Coefficients in Mixed Electrolytes|first1=R. H.|last1=Betts|first2=Agnes N.|last2=MacKenzie|journal=Canadian Journal of Chemistry|volume=30|issue=2|pages=146–162|doi=10.1139/v52-020|year = 1952}}</ref>

=== At infinite dilution ===
Activity coefficients for binary mixtures are often reported at the infinite dilution of each component. Because activity coefficient models simplify at infinite dilution, such empirical values can be used to estimate interaction energies.  Examples are given for water:

{| class="wikitable"
|+ Binary solutions with water<ref>{{cite web |title=Activity Coefficients at Infinite Dilution of 30 Important Components from Dortmund Data Bank |url=http://www.ddbst.com/en/EED/ACT/ACTindex.php |website=Dortmund Data Bank |publisher=DDBST GmbH |access-date=13 December 2018}}</ref>
|-
! X
! {{math|γ<sub>x</sub><sup>∞</sup>}} (K)
! {{math|γ<sub>W</sub><sup>∞</sup>}} (K)
|-
| [[Ethanol]] || 4.3800 (283.15) || 3.2800 (298.15)
|-
| [[Acetone]] || || 6.0200 (307.85)
|}