The Theory Of Dynamic Equilibrium Essay
The Ka value of a weak acid can be found experimentally using a pH meter along with the concept of equivalence point when titrating an acid and a base. One half of the weak acid has been titrated at the half-equivalence point, meaning that the concentration of weak acid [HA] and its conjugate base [A—] are equivalent. As seen in the Equation (1), equal values for the concentrations of weak acid [HA] and conjugate base [HA] cancel each other out, mathematically. The result is Equation (2) shown below. Equation (2) provides a value for Ka only applicable at the half-equivalence point.
By manipulating Equation (2), further mathematical relationships can be derived. For example, Equation(3) can be found by taking the log of both sides:
The previously shown mathematical relationships [Equations (1-4)] were applied to the titration of a strong base and a weak acid performed in this experiment. NaOH was the strong based utilized, with a known concentration of 0.095 M. The purpose of this experiment was to determine the concentration of the weak acid , which was completed using Equation (5), where M1 was equal to the concentration of NaOH, V1 was equal to the volume of base used to titrate, and V2 was…