Question

Use the information below to answer the six questions that follow. Buffer A is 25.0mM potassium phosphate, pH7.0,1mM EDTA. Formula weights of anhydrous monobasic and dibasic potassium phosphate are KH2PO4 (FW: 135 g/mol ) and K2HPO4 (FW: 175 g/mol ), respectively. The pKa of the monobasic / dibasic phosphate buffer is 6.825 . In order to make Buffer A, 1.0M stock solutions of KH2PO4 and K2HPO4 are available. Question 4 1.5 pts Relative to Buffer A, the 1M monobasic and dibasic stocks are X more concentrated. a. 40 b.39 c. 25 d. 20

Answer 1

To determine the relative concentration of the 1M monobasic and dibasic stocks compared to Buffer A, we can calculate the dilution factor. The monobasic and dibasic stocks are 40 times more concentrated than Buffer A.

Step-by-step explanation:

To determine the relative concentration of the 1M monobasic and dibasic stocks compared to Buffer A, we can calculate the dilution factor. The concentration of Buffer A is 25.0mM, which is equivalent to 0.025M. The monobasic stock solution is 1.0M, so its dilution factor is 0.025/1.0 = 0.025. Similarly, the dibasic stock solution is also 1.0M, so its dilution factor is also 0.025.

Therefore, both the monobasic and dibasic stocks are 40 times more concentrated than Buffer A. So, the correct answer is a. 40.