Question

What is the pH of a solution if 7.59 mL of 0.10 M HCl is added to the buffer obtained by mixing 173.38 mL of 0.50 M CH₃NH₂ and 231.71 mL of 1.0 M CH₃NH₃Cl⁻?
a. 9.55
b. 10.12
c. 9.35
d. 10.48