1. The ionic solid (NH₄)₂SO₄is a strong electrolyte and dissolves 100% in aqueous solution. If 52.9 g solid (NH₄)₂SO₄dissolves into 100 mL water, please answer the following three question:

(1) Write the balanced equation for ion dissociation.

(2) How many moles of SO₄^2-ions are present in the solution?

(3) What is the molarity of NH₄⁺?

2. A 0.0250 M solution of Mn(NO₃)₂is reacted with 0.268 g PbO₂. The balanced equation is

2Mn(NO₃)_{2 (aq)}+5PbO_{2 (s)}+ 6 HNO₃ 5 Pb(NO₃)₂+ 2 HMNO₄+ 2 H₂O

How many liters (L) of the Mn(NO₃)₂solution is needed to use up all of the PbO₂?

(Notes: Molarity (M) = mol/L; PbO₂= 239.2 g/mol)