Use the Henderson-Hasselbalch equation. Note the correct selling of chemistry. ALSO, and this is important, do you man m or M. m stands for molality. M stands for molarity. Also, I don't believe Ka for acetic acid is 1.76 x 10^-6. You either looked it up wrong or y you made a typo. Most tables list it as 1.75 (or 1.76) x 10^-5.
