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A solution contains potassium iodide and potassium chloride - HSC - SSCE Chemistry - Question 16 - 2023 - Paper 1
Question 16
A solution contains potassium iodide and potassium chloride. It was analysed by performing a precipitation titration using silver nitrate. The titration curve for th... show full transcript
Worked Solution & Example Answer:A solution contains potassium iodide and potassium chloride - HSC - SSCE Chemistry - Question 16 - 2023 - Paper 1
Step 1
B. I would precipitate out first, followed by AgCl.
Answer
In this titration, silver nitrate (AgNO3) is added to the solution to precipitate the anions. Potassium iodide (KI) and potassium chloride (KCl) dissociate into potassium ions and their respective anions, I⁻ and Cl⁻. Silver ions (Ag⁺) will react with I⁻ to form silver iodide (AgI), which is less soluble and precipitates out of the solution before AgCl, due to its lower solubility product (Ksp). Thus, the precipitation of AgI occurs first, followed by the precipitation of AgCl as the titration proceeds. This phenomenon allows for the accurate quantification of each anion in the original mixture.