Final answer:
The concentrations of all solute species in 0.150 M lactic acid can be calculated using the acid's ionization constant and setting up an equilibrium expression to find the equilibrium concentrations of hydronium ions and lactate anions.
Step-by-step explanation:
Determining the Concentrations of Solute Species in Lactic Acid
When determining the concentrations of all solute species in a 0.150 M solution of lactic acid, HC₃H₅O₂, it is necessary to consider the dissociation of lactic acid in water.
Lactic acid (HC₃H₅O₂) is a weak acid that partially dissociates in water according to the following equilibrium:
HC₃H₅O₂(aq) → H+(aq) + C₃H₅O₂⁻(aq)
The degree of dissociation is governed by the acid's ionization constant, Ka. Given the Ka value for lactic acid of 1.36 × 10⁻⁴, we can set up an equilibrium expression to solve for the concentration of hydronium ions (H+) and lactate anions (C₃H₅O₂⁻) at equilibrium.
The initial concentration of lactic acid is given as 0.150 M, with no initial concentrations of H+ or C₃H₅O₂⁻. As lactic acid dissociates, the concentration of H+ and C₃H₅O₂⁻ will increase, while the concentration of undissociated lactic acid will decrease. The changes can be represented in an ICE table (Initial, Change, Equilibrium), allowing us to solve for the equilibrium concentrations.
At equilibrium, the concentrations will be determined using the relationship between the initial concentration, the change (which we'll call 'x'), and using the Ka expression:
Ka = [H+][C₃H₅O₂⁻] / [HC₃H₅O₂]
This equation will allow us to solve for 'x', the change in concentration and, subsequently, the final concentrations of all species.