If you add another atom of oxygen to water what do you get?

Question or possible answers should be changed. 1 atom in a small cup of water would still be water. A 1% solution can be used as a mouthwash or for debriding (rinsing away debris). A 3% solution can have medical usage as an antiseptic. But in pure form it acts as a poison.

The majority is almost always wrong. Such a useless hint.

TestyAlien3443, I agree. It has many medicinal uses.