Write down the equations for the dissociation of phosphoric acid, potassium hydroxide and aluminum sulfate.

We write down the equation of dissociation of phosphoric acid. Dissociation of the compound takes place in three stages. We write it down.
H3PO4 = H + + H2PO4-
H2PO4- = H + + HPO42-
HPO42- = H + + PO43-
Abridged version.
H3PO4 = 3H + + PO4 (3-).
That is, phosphoric acid dissociates into a hydrogen cation and a phosphate anion.

We write down the equation of dissociation of potassium hydroxide.
KOH = K + + OH-.
Potassium hydroxide dissociates into a potassium cation and an anion of a hydroxo group.

We write down the equation of dissociation of aluminum sulfate.
Аl2 (SO4) 3 = 2Al3 + + 3SO4 (2-).
Aluminum sulfate dissociates into aluminum cation and sulfate anion.