A 100 mL beaker contains 10 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker, 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing?
A) The concentration of Na+ ion rises.
B) The concentration of Cl- ion falls.
C) The concentration of undissociated H2O molecules remains unchanged.
D) The pH of the beakerʹs contents rises.
E) The pH of the beakerʹs contents falls.
Answer: E) The pH of the beakerʹs contents falls.