 Before we go on to show how this problem was solved, let me give you a few extra bits of information. Firstly, a hydrogen ion is commonly referred to as a proton. This is because it is literally a proton. Remember that a hydrogen atom consists of one proton and one electron. So when it becomes an ion, it loses the electron, and so an H plus ion is actually a naked proton. This name also leads to the classification of acids as monoprotic, diprotic, or triprotic. All this means is, when the acid dissolves in water, what is the maximum number of hydrogen ions that can dissociate from one molecule? For instance, nitric acid and hydrochloric acid are both monoprotic, because when they dissociate, they release one proton or one hydrogen ion per molecule. Sulfuric acid is a diprotic acid, and phosphoric acid is a triprotic acid. It releases three hydrogen ions. Secondly, naked protons do not tend to hang around for long. When they're produced in water by an acid molecule dissociating, they will quickly join up with a water molecule to make this ion, which is called the hydronium ion. So it's important to remember that, although we often talk about acids as producing hydrogen ions or protons, in reality these protons would almost instantly be converted into hydronium ions. However, we generally use these two names, hydrogen, well three names, hydrogen ions, protons, and hydroniums interchangeably when we're talking about acids and their effects in water.