Hcn + Hf --> ? 1. The problem statement, all variables and given/known data -What do HCN + HF form? (I've googled the reaction, can't find anything). -Also, what're 3 good characteristics of an acid-base indicator? 2. Relevant equations 3. The attempt at a solution I know it's an acid-base reaction. I'm guessin something like HCN + HF --> NH3 + CF -One good characteristic of an acid base indicator would be an intense colour change?