# Using Henderson-Hasselbalch equation, how do you find pH of a solution that is 11.5g HF and 22.5 g NaF in 125 ml of solution?

$p H$ $=$ $p {K}_{a} + {\log}_{10} \left(\frac{\left[{F}^{-}\right]}{\left[H F\right]}\right)$
You can easily work out the concentrations of hydrogen fluoride and its conjugate base with the info given. You will have to find the $p {K}_{a}$ of $H F$.