When 0.85mol of zinc nitrate react with 0.254mol of sodium phosphate insoluble zinc phosphate forms. Which is the limiting reactant and which is the reactant in excess?
zinc nitrate = Zn(NO3)2
sodium phosphate = Na3PO4
zinc phosphate = Zn3(PO4)2
Balanced chemical equation:
3Zn(NO3)2(aq) + 2Na3PO4(aq) → Zn3(PO4)2(s) + 6NaNO3(aq)
According to stoichiometry:
3 mol of Zn(NO3)2 reacts with 2 mol of Na3PO4
Thus 0.85 mol of Zn(NO3)2 reacts with:
(0.85 mol Zn(NO3)2) × (2 mol Na3PO4 / 3 mol Zn(NO3)2) = 0.57 mol Na3PO4
However, initially there is 0.254 mol of Na3PO4 (according to the task).
Thus, Na3PO4 acts as limiting reactant and Zn(NO3)2 is excess reactant.
Na3PO4 is the limiting reactant.
Zn(NO3)2 is the reactant in excess.