The concept of dynamic equilibrium can be understood using the properties of a titration of a strong base with a weak acid, including its equivalence point and half-equivalence point. The following equation demonstrates the dynamic equilibrium achieved when using a weak acid:
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 …show more content…
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 equal to volume of weak acid used. M2 or the concentration of weak acid, was calculated for each of the three trials.
Beyond this experiment, the concepts of pKa, Ka, and pH are utilized in the disciplines of chemistry and biochemistry, specifically in the food industry. Weak acids can have antimicrobial properties when protonated, making them useful in the preservation of acidic foods. The charge of proteins and carbohydrates is dependent on pH, meaning that weak acids play a key role in stabilizing the texture of dairy products, jellies, and marmalades. Finally, weak acids have the ability to alter the flavor of foods and act as buffering agents. These many roles of weak acids make the concepts of pKa, Ka, and pH vital to the food …show more content…
The titration may have been ended too promptly, although this source of error can be ruled out by graphing the titration curve for each of the three trials. A lack of sufficient number of data points surrounding the equivalence point could have been an additional source of error. Despite sufficient data, the failing to properly standardize the pH meter could have affected the accuracy of the titration curve. Improper calibration of the machine would have only affected the accuracy of the data, and not the precision, demonstrated by the low standard deviation.
Conclusion
The titration of a weak acid with a strong base possesses the ability to demonstrate many of the characteristics of the weak acid. In this experiment, the pH and consequently pKa and Ka of an unknown acid were determined. The principles used in this experiment including titration, pH and Ka play an important role in the fields of chemistry and biochemistry, especially in the food
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 …show more content…
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 equal to volume of weak acid used. M2 or the concentration of weak acid, was calculated for each of the three trials.
Beyond this experiment, the concepts of pKa, Ka, and pH are utilized in the disciplines of chemistry and biochemistry, specifically in the food industry. Weak acids can have antimicrobial properties when protonated, making them useful in the preservation of acidic foods. The charge of proteins and carbohydrates is dependent on pH, meaning that weak acids play a key role in stabilizing the texture of dairy products, jellies, and marmalades. Finally, weak acids have the ability to alter the flavor of foods and act as buffering agents. These many roles of weak acids make the concepts of pKa, Ka, and pH vital to the food …show more content…
The titration may have been ended too promptly, although this source of error can be ruled out by graphing the titration curve for each of the three trials. A lack of sufficient number of data points surrounding the equivalence point could have been an additional source of error. Despite sufficient data, the failing to properly standardize the pH meter could have affected the accuracy of the titration curve. Improper calibration of the machine would have only affected the accuracy of the data, and not the precision, demonstrated by the low standard deviation.
Conclusion
The titration of a weak acid with a strong base possesses the ability to demonstrate many of the characteristics of the weak acid. In this experiment, the pH and consequently pKa and Ka of an unknown acid were determined. The principles used in this experiment including titration, pH and Ka play an important role in the fields of chemistry and biochemistry, especially in the food