1. Effect of the dissociation constant of the acid (Ka) on the shape of the titr
ID: 501838 • Letter: 1
Question
1. Effect of the dissociation constant of the acid (Ka) on the shape of the titration curve. The value of Ka affects the shape of the titration curve for a weak acid/strong base titration. Increase and decrease the value of Ka and see how the shape changes. For example, change the value of Ka from 1.75 x 10-5 to 1.75 x 10-7 and then to 1.75 x 10-4 . Notice that the height of the curve changes as Ka changes. Also note how the pH of the solution at the end point changes as Ka changes. How does the pH of the solution at the end point vary with Ka and why does it vary with Ka?
If you were to carry out a titration with weak base in the flask and a strong acid in the buret, how would the pH of the solution in the flask vary as acid is added to the solution? Would the pH of the solution at the end point be acidic or basic?
Explanation / Answer
In the case of titrating the acid into the base for a strong acid-weak base titration, the pH of the base will ordinarily start high and drop rapidly with the additions of acid. As the equivalence point is approached, the pH will change more gradually, until finally one drop will cause a rapid pH transition through the equivalence point. If a chemical indicator is used methyl orange would be a good choice in this case it changes from its basic to its acidic color.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.