Final answer:
C) Keq .The equilibrium constant for sodium propanoate in solution is best represented by Keq, which is used for the equilibrium condition of a reaction in a homogeneous phase such as a solution.
Step-by-step explanation:
The equilibrium constant for sodium propanoate in an aqueous solution is best represented by Keq which stands for the equilibrium constant. In general, the term Keq is used to describe the equilibrium condition of a reaction where the ratio of the concentration of the products to the reactants is constant, at a fixed temperature.
The equilibrium constant can be given in different forms depending on the nature of the reactants and products. For reactions involving gases, Kp is used, and it is related to the partial pressures of the gases.
For reactions in solution, Kc is often used and considers the molarity of reactants and products. In the case of a salt like sodium propanoate dissolving in water, Keq would be more appropriate.
Furthermore, if the salt was sparingly soluble, its solubility product, represented by Ksp, would be relevant. However, Ksp typically applies to the equilibrium between a solid and its ions in solution, which is not directly applicable here since sodium propanoate is fully soluble.