Final answer:
The one molar solution of KI will yield the largest mass of silver halide precipitate per liter of solution when treated with an excess of silver nitrate.
Step-by-step explanation:
When treated with an excess of silver nitrate, the solution that will yield the largest mass of silver halide precipitate per liter of solution is the one molar solution of KI. This is because the solubility product constant (Ksp) for silver iodide (AgI) is much smaller than the Ksp values for silver chloride (AgCl) and silver bromide (AgBr). As a result, more AgI will precipitate compared to AgCl and AgBr when excess silver nitrate is added to the solution.