In order to find the [H+] ion content of H2SO4 (Sulphuric Acid), why must you divide by two after using the formula for pH calculation?

This is because H2S04 is a diprotic acid. If we look at how the acid dissiociates, we can see that:

H₂SO₄----------> 2H⁺+SO₄^2-

Since there are two H⁺ ions dissociating, using the formula for pH would give the H⁺ ion content within the whole acid, i.e 2H⁺

Dividing it by two would equate to a singular H⁺, which is what the question asks.