Answer
There are two factors affecting the relative acidity of an oxyacid: the electronegativity of the central atom, and the number of oxygen atoms attached to the central atom.
Work Step by Step
See the topic: "Oxyacids" on page 763, Section 16.10.
There are two factors affecting the relative acidity of an oxyacid: the electronegativity of the central atom, and the number of oxygen atoms attached to the central atom.