Answer:
D. H2SO4
Explanation:
The chemical formula of a compound is an expression that stares out the elements (in form of symbols)present in a compound and the number of the atoms.
In the image;
There is one sulphur (S) atom, 4 oxygen(O) atoms and 2 hydrogen (H) atoms
The chemical formula is;
H2SO4.
The correct option is option D.
Answer: The equation is written below.
Explanation:

According to Stoichiometry of the reaction:
2 moles of phosphate ions reacts with 1 mole of aluminum sulfate to produce 2 moles of aluminum phosphate precipitate and 3 moles of sulfate ions.
Aluminum phosphate is an odorless and white crystalline solid
The chemical equation is written above.
*base
a base is added to an acid to neutralize it.