Question

an ion formed when anion form when hydrogen ion combines with a water molecule

Answer 1

This thing (made up of a proton (H+) added to a water molecule is an ion because it has a charge. Its formula is H3O+ and its called the hydronium ion. The hydroniumion always forms when an acid dissolves in water. The H+ from the acid always goes to the nearest water molecule and forms H3O+.