A 100 L Buffer Solution Is 0

A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in LiF.Calculate the pH of the solution after the addition of 0.150 moles of solid LiOH.Assume no volume change upon the addition of base.The K_a for HF is 3.5 × 10^-4.

A) 3.46
B) 4.06
C) 2.85
D) 3.63
E) 4.24