Finding pH of solutions with an acid and base

[mirandab17]

What is the pH of the solution formed when 0.040 mol KOH is added to 2.00 L of 0.020 m HCl?

Hello all!

I'm really struggling with this. I set up the change table with the reaction of KOH + HCl <> H2O + KCl, and so I end up with Ka = x/(.01-x)(0.2-x). What Ka value would I use?

I may be completely wrong. Please help.

 

[Borek]

Both are strong, so it is just a limiting reagent question. Whatever is left is responsible for the final pH. If nothing is left, than you have just water solution of NaCl.

Could be you are expected to take ionic strength into account.