Question

A stock of 1M acetic acid and a stock of 1M sodium acetate are used to prepare three different buffers by mixing them at different volume ratios, as given in the table below. Which of following statements is true?

1M CH3COOH 1M CH3COONa

Buffer A: 10 mL 90 mL

Buffer B: 40 mL 60 mL

Buffer C: 80 mL 20 mL

which of the following:

A) pH of buffer A = pH of buffer B = pH of buffer C

B) pH of buffer A > pH of buffer B > pH of buffer C

C) pH of buffer A < pH of buffer B < pH of buffer C

D) a comparison of the resulting pH cannot be made without knowing the exact pKa of CH3COOH

E) none of the answer is correct