I'd like to welcome you,
screechy: to the chemical forums, but I'd like to remind you to read the
Forum Rules{click}. You agreed to read and follow them when you signed up, and they apply to everyone, we'd like to see your attempt first.
Now then:
What is potassium periodate used for? Does it have any purpose or uses?
OK, I'll bite. Where did you hear of it? You sure this reagent exists, so in what sense are you asking the question. Can you think of a better question to ask?
Consider NaCl. It exists. What do we use it for? Cause if we don't, we'll die. Does knowing that help you understand NaCl better?