An aqueous mixture contains 0.050 M aluminum nitrate and 0.050 M sodium chloride in a…
CHEMISTRY · Multi-part · A Level · Chemistry · Reactions of ions in aqueous solution · Reactions of ions in aqueous solution
Problem
An aqueous mixture contains 0.050 M aluminum nitrate and 0.050 M sodium chloride in a total volume of 250 mL. A chemist first adds 0.10 M sodium phosphate solution dropwise until precipitation ceases, filters the resulting mixture, and then adds excess 0.10 M silver nitrate solution to the clear filtrate.
(a) Predict which compound precipitates first when sodium phosphate is added. Write the balanced net ionic equation for this precipitation reaction.
(b) After filtration, silver nitrate is introduced. Write the balanced net ionic equation for any new precipitation reaction that occurs with the remaining ions.
(c) For each step (addition of sodium phosphate and addition of silver nitrate), list all spectator ions present in the reaction mixture and explain why they remain in solution.
(d) Using solubility rules, justify how the sequence of reagents allows selective separation of aluminum and chloride ions from the original mixture.