To write the complete balanced molecular equation, you first write the formulas for the reactants and products, then balance the equation by adjusting the coefficients to make sure the number and type of atoms on both sides are equal. In your equation, you started with NiCl2 + Na2(PO4)Ni = (PO4)Ni + NaCl.
However, it seems like you made a mistake in writing the formulas. Nickel (II) chloride is actually NiCl2, and sodium phosphate is Na3PO4. So, the correct molecular equation for the reaction is:
NiCl2 + Na3PO4 -> Ni3(PO4)2 + 2NaCl
Next, to write the ionic equation, you need to break apart the soluble compounds into their respective ions. In this case, NiCl2 dissociates into Ni2+ and 2Cl- ions, and Na3PO4 dissociates into 3Na+ and PO4^3- ions. The equation becomes:
2Ni2+ + 3PO4^3- + 6Na+ + 6Cl- -> Ni3(PO4)2 + 6Na+ + 6Cl-
Finally, you can cancel out the spectator ions (the ions that are present on both sides of the equation) to write the net ionic equation. In this case, the Na+ and Cl- ions are present on both sides and cancel out, leaving:
2Ni2+ + 3PO4^3- -> Ni3(PO4)2
So, the net ionic equation is: 2Ni2+ + 3PO4^3- -> Ni3(PO4)2
The precipitate is the solid that forms during a chemical reaction. In this case, the net ionic equation shows the formation of Ni3(PO4)2, which is insoluble (does not dissolve) in water. Therefore, Ni3(PO4)2 is the precipitate in this reaction.