Homework Help: Salt Solution problem

1. Feb 26, 2010

temaire

1. The problem statement, all variables and given/known data

A solution of $$NH_4F$$ would be:
a) acidic
b) neutral
c) basic

3. The attempt at a solution

I think the solution would be acidic because it is a salt made of a weak acid and a weak base. Since the Ka for HF is greater than the Kb for NH3, the Ka for NH4+ is greater than the Kb for F-. Thus, the solution is acidic. Am I right?

2. Feb 27, 2010

epenguin

I think your reasoning is sort of OK, however I would like to add for you to make this secure:

I don't know if you are up with pH's and pK's yet, but the pH of solution equimolar amounts of weak acid and weak base is half way between the pKa's of both.