(1)

How can I figure this out using solubility? I know I need to find a reagent that will form precipitate with Ag+ or Na+

You are the manager of a chemical stockroom, and find a bottle containing approximately one liter of a clear and colorless solution of unknown identity and concentration. Your only clue to its identity is that it was found between bottles of silver fluoride and sodium fluoride, so it is likely an aqueous solution of one of those two compounds. You will need to develop a procedure to determine the following:

a) The identity of the unknown solution

b) The concentration of the unknown solution