A chemist mixes an aqueous solution of sodium hydroxide with an aqueous solution that…
CHEMISTRY · Multi-part · A Level · Chemistry · Reactions of ions in aqueous solution · Reactions of ions in aqueous solution
Problem
A chemist mixes an aqueous solution of sodium hydroxide with an aqueous solution that contains both aluminum chloride and ammonium sulfate. The chemist’s particulate-level observation after vigorous stirring is summarized below.
• Solid gelatinous clusters composed of aluminum and oxygen atoms are dispersed throughout the liquid but slowly settle over time.
• The aqueous phase contains the following freely dispersed ions in the indicated mole ratios: 3 Na^+, 2 NH₄^+, 1 SO₄^2−, and 3 Cl^−.
• No other species are present.
(a) Based on the ions remaining in solution, determine the limiting reactant among the three dissolved solutes originally present before reaction.
(b) Write balanced molecular equations for all precipitation and acid–base reactions that occurred when the two solutions were combined.
(c) For each molecular equation in part (b), derive the corresponding net ionic equation.
(d) Demonstrate explicitly that the total positive charge equals the total negative charge in the final mixture (solid plus solution).