ABSTRACT
The calculation of the equilibrium state of any reaction involving components in condensed solution requires knowledge of the thermodynamic properties of the various solutions present in the system. This chapter examines the influence of solution thermodynamics on reaction equilibria. At reaction equilibrium, the activity quotient is numerically equal to the equilibrium constant K. In situations in which the pure component exists in a physical state which differs from that of the solution, the Henrian standard state may be more convenient than the Raoultian standard state. Such situations include the solution of a gas in a solid or liquid solvent and the solution of a solid in a liquid solvent. The value of the equilibrium constant for any reaction, being equal to the quotient of the activities of the reactants and products at reaction equilibrium, necessarily depends on the choice of standard states for the components.
