pls help i need the answer not jus part of it, pls im really stuck out here.

A buffer was prepared by dissolving 0.100 mol of the weak acid HA (Ka = 1.00 × 10−5) plus 0.050 mol of its conjugate base Na+A− in 1.00 L. Find the pH.

I would MUCH prefer that you know how to solve these.

What do you not understand about using the Henderson-Hasselbalch equation?