I did this question before and the answer is Magnesium and silicon, B.
We can solve this problem using the long hand solution, wherein we 1 by 1 analyze the different equilibrium reactions or by simply using the Henderson Hasselbach equation. The equation is
pH = -log(pKa) + log (salt/acid)
since the acid and the salt have the same concentration, the log (salt/acid) term is equal to zero.
thus
pH = -log(1.73*10-5)
pH = 4.76
please be careful with the negative sign
When you work with molar mass, you solve for the quantity of ''Moles'' within the substance by converting Mass. The way you can tell the equation is balanced would be by knowing whether the moles were equivalent on both sides or not. Therefore, if they are equal, it is balanced considering you have the same amount of moles on each side of the equation.
