What Is the PH of the Resulting Solution If 45

Multiple Choice

What is the pH of the resulting solution if 45 mL of 0.432 mol L^-1 aqueous methylamine,CH₃NH₂,is added to 15 mL of 0.234 mol L^-1 HCl(aq) ?
Assume that the volumes of the solutions are additive.K_a = 2.70 × 10^-11 for CH₃NH₃⁺.

A) 2.77
B) 4.09
C) 9.91
D) 11.23