[FascinatingPens]

This problem is killing me.

What mass of NaOH(s) must be added to 1.0 L of 0.050 M NH₃ to ensure that the percent ionization of NH₃ is no greater than 0.0010%? Assume no volume change on addition of NaOH.

First, I wrote out NH₃ + H₂O   OH^- + NH₄⁺ and set up an ICE table. Then I realized that I had to figure out how NaOH would affect the system. I know Na⁺ wouldn't do anything, and OH^- would shift the equilibrium to the left. I thought I could use LeChâtelier's principle, but that wouldn't tell me how much the equilibrium would shift. I have no idea where to go from here. Can someone please help me?

[Borek]

http://www.titrations.info/acid-base-titration-indicators

This is about indicators, but take a look at the equations at the very begining of the page, they nicely fit your problem. Especially left side of the second equation.