Figure 2-1 Refer to Figure 2-1. What Affect Was There on the There

Figure 2-1
Refer to Figure 2-1. What affect was there on the pH of the solution when the volume of base added was increased from 8 mL to 13 mL?

A) The pH dropped by a value of 4.
B) The pH increased by a value of 4.
C) The pH remained relatively unchanged.
D) The pH increased by a value of 10.
E) The pH increased by a value of 20.