text: For multicomponent solutions, apparent molar properties can be defined in several ways. For the volume of a ternary (3-component) solution with one solvent and two solutes as an example, there would still be only one equation , which is insufficient to determine the two apparent volumes. (This is in contrast to partial molar properties, which are well-defined intensive properties of the materials and therefore unambiguously defined in multicomponent systems.  For example, partial molar volume is defined for each component i as .)
  One description of ternary aqueous solutions considers only the weighted mean apparent molar volume of the solutes, defined as 
  where  is the solution volume and  the volume of pure water.
  This method can be extended for mixtures with more than 3 components.
  The sum of products molalities – apparent molar volumes of solutes in their binary solutions equals the product between the sum of molalities of solutes and apparent molar volume in ternary of multicomponent solution mentioned above.
  Another method is to treat the ternary system as pseudobinary and define the apparent molar volume of each solute with reference to a binary system containing both other components: water and the other solute.  The apparent molar volumes of each of the two solutes are then
  : and 
  The apparent molar volume of the solvent is:
  However, this is an unsatisfactory description of volumetric properties.
  The apparent molar volume of two components or solutes considered as one pseudocomponent  or  is not to be confused with volumes of partial binary mixtures with one common component  V, V which mixed in a certain mixing ratio form a certain ternary mixture V or V.
  Of course the complement volume of a component in respect to other components of the mixture can be defined as a difference between the volume of the mixture and the volume of a binary submixture of a given composition like:
  There are situations when there is no rigorous way to define which is solvent and which is solute like in the case of liquid mixtures (say water and ethanol) that can dissolve or not a solid like sugar or salt. In these cases apparent molar properties can and must be ascribed to all components of the mixture.