Can you help me and question 2 and 2and 4? 1. Using the average pKa from Table 1
ID: 1022574 • Letter: C
Question
Can you help me and question 2 and 2and 4? 1. Using the average pKa from Table 1 and Appendix D in your textbook, determine the likely identity of this buffer system. There may be more than one possibility: think what we would be likely to have on hand in lab. (5 pts) According to the data collected in Table 1, is the pH of a buffer dependent on its formal concentration (FHA)? (FHA [HA]+ [A]) Explain. (5 pts) 2. Describe your observations in terms of the buffer capacities of solutions E, F and G. Which is the best buffer against the addition of acid and base? Which is the worst? Why did you pick the buffers that you did? (5 pts) 3. For trials N and Q, was the buffer capacity of the solution destroyed by the addition of the acid and base? Rationalize your results (i.e. provide a chemical explanation of your 4. results). (10 pts)Explanation / Answer
Q2.
IF you were to add a column in which you add both species,
F HA = HA + A-
You will se that as the Formal Concentration increases, the pH is clearly changing (actually increasing as well)
therefore
IT DOES DEPEND
Q4.
Recall that buffer capacity is the ability of a solution to "buffer" the change in pH, that is, if we add an acid or a base, it should not change that much (typically changes of pH = 1)
In "N"
We clearly destroyed the buffer capacity. Since th epH change is 1.09, therefore it was too much change. It is considered "destroyed"; if we add more acid, then we will decrease the pH drastically
For "Q"
we have a pretty drastic change in pH, 6.8; this is too much since we are neutralizing the acid. It is, by definition, a bad buffer; since it not only got destroyed (its capacity) but it is changing from acidic to neutral. Then it goes from neutral to basic.