Question

fertilizers contain ammonium ion which can be toxic Suppose the toxicity level of the ammonium ion is 0.38 mol / L and above If 8.19 g of ammonium phosphate are dissolve in water to create 432 Ml of solution would this be considered toxic

Answer 1

The dissociation of ammonium phosphate in water can be described as following:

(NH₄)₃PO₄ = 3NH₄⁺ + PO4^-

From here, the mass of ammonia ions in the solution equals:

m (NH₄⁺) = [m((NH₄)₃PO₄) × 3 × Mr(NH₄⁺) ]/Mr((NH₄)₃PO₄) = (8.19 g × 3 × 18.04 g/mol) / 149.09 g/mol = 2.97 g

The molarity of ammonium ions in the solution equals:

n (NH₄⁺) = m(NH₄⁺) / [Mr(NH₄⁺) × V(solution)] = 2.97 g / (18.04 g/mol × 0.432 L) = 0.381 mol/L

Answer: As toxicity the toxicity level of the ammonium ion is 0.38 mol / L, the solution of ammonium phosphate is toxic.