In one of my events for Science Olympiad, I am given a water sample and must test for certain anions and cations. This wouldn't be a problem, except for the only chemicals we are given are HCl and NaOH. We are provided kits for certain ions, like phosphate and nitrate, but on the last test we were required to test for Cl- ions and there was no kit for that. Other ions include, Pb2+, Ca2+, K+, Na+. I have no idea how to test for these without bringing in other kits or chemicals, but we are not allowed to do that. Kits for some of these ions may be provided, but based on the last test with the Cl- ion where we didn't have a kit, there must be some other way to tell. Does anyone have any ideas?