Reactions | The One Where We Put Stuff in Acid | Season 4 | Episode 38 | PBS

Watch as Reactions uses some acid know-how to tell a chemistry detective story and sort real gold from the imposters. Acids are reactive, and even weak acids like vinegar can wow people with their reactivity. But strong acids can really put on a show, dissolving otherwise relatively inert metals. And aqua regia, or royal water, is a mixture of hydrochloric and nitric acids that can dissolve gold.