What Is the PH After the Addition of 0

Multiple Choice

What is the pH after the addition of 0.050 moles of NaOH to 1.00 L of a 0.500 M NH₃ / 0.500 M NH₄Cl buffer solution?
Assume that there is no volume change on addition of the NaOH. K _b for NH₃ = 1.8×10 ^{- 5}.

A) 4.74
B) 4.66
C) 9.34
D) 9.17
E) 9.53