[webguy54]

I'm studying salt ionization.  To calculate the pH of a salt from a weak acid + strong base reaction, I can use the equation: pH = 1/2 pkw + 1/2 pka + 1/2 log C.

To calculate the pH of a salt from a weak base + strong acid  reaction,
I can use the equation: pH = 1/2 pka - 1/2 log C.

We won't be given chemical reactions. Here is an example question: "Calculate the pH of 0.1M ephedrine HCl in water. Pka = 9.36." According to the example in the book I use the second equation listed (weak base/strong acid). A similar question involves lidocaine HCl.

How can I tell which salt is produced and which equation to use? If the drug has HCl after the name, does that mean it's derived from HCl (a strong acid)?