Now in our exploration to understand ionic salts, we've now come to an ions. Anions represent negatively charged ions. Anions can either be basic or neutral based on their acceptance of a proton. Now remember, a proton is just represented by an H ion. If we take a look here, we're going to say add an H to the anion. If a weak acid is created, then your anion is basic.

So if we take a look here, we have potassium fluoride, so it breaks up into K⁺ and F^-. F^- is our anion. We're going to add an H⁺ to it. When we do that, we create HF, which is hydrofluoric acid, which is a weak acid. That means that the fluoride ion is basic. That's because here we have a weak acid. If you're a weak acid, you're going to create a stronger conjugate base, just strong enough that it's classified as being basic.

Over here on this side, when we add an H⁺ to an anion, if a strong acid is created then the anion is neutral. Here we have sodium chloride which breaks up into sodium ion plus the chloride ion. Here we're going to add an H⁺ to the chloride ion to give us HCl hydrochloric acid, which is a strong acid. Because we created a strong acid, that means it's conjugate base is going to be extremely weak. So weak that we see it as being neutral. So this chloride ion here would be neutral.

So just remember when we have a negatively charged ion, add an H⁺ to it. If you create a weak acid then the negative ion is basic. If you create a strong acid, then the negative ion will be neutral.