Lilly

Biology

7 December, 04:04

A student is preparing a solution of 0.1 M Tris-Cl (pH 7.0) with 200 mM NaCl. To adjust the pH, the student started with concentrated HCl and overshot, reducing the pH to 4.0. To correct this, the student added NaOH until the pH reached 7.0 and then brought the solution to volume. Which of these statements describes the prepared buffer?

a. The buffer is correctly prepared.

b. The pH is not accurate because both acid and base were used.

c. The pH is accurate, but the solution will have excess salt.

d. The pH is accurate, but the concentration of Tris will be incorrect.

e. The pH is accurate, but the volume will be too high.