In the formula xso4, the symbol x could represent the element

The answer is: Mg.

Sulfate anion (SO₄²⁻) has negative charge, so element X must be element with positive charge +2.

Magnesium (Mg) is metal from 2. group of Periodic table of elements, it lost two electrons to form magnesium cation (Mg²⁺).

Magnesium has atomic number 12, which means it has 12 protons and 12 electrons.

It lost two electrons to form magnesium cation (Mg²⁺) with stable electron configuration like closest noble gas neon (Ne) with 10 electrons.

Electron configuration of magnesium atom: ₁₂Mg 1s² 2s² 2p⁶ 3s².  

Electron configuration of magnesium ion: ₁₂Mg²⁺ 1s² 2s² 2p⁶.  

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

the ratio of the conjugate base to the acid required to attain the desired ph.