A 500-ML Sample of 0 $\times$ 10^-4)is Titrated with 0

Multiple Choice

A 50.0-mL sample of 0.10 M HNO₂ (K_a = 4.0 $\times$ 10^-4) is titrated with 0.12 M NaOH.The pH after 25.0 mL of NaOH have been added is

A) 10.43
B) 7.00
C) 6.57
D) 3.57
E) none of these