0.041 M
Chemically, “complete” does not mean zero ions. A common answer key phrase: “Complete precipitation is often defined as when the ion concentration drops below (10^{-5} M) or (10^{-6} M).” Fractional Precipitation Pogil Answer Key
The local [Cl⁻] near the dropping point could exceed 0.041 M, causing PbCl₂ to precipitate prematurely. This leads to co-precipitation (contamination of the AgCl solid with PbCl₂). Hence, slow addition with stirring is critical. 0.041 M Chemically
Use these to test your understanding of the principles laid out in the answer key above. Fractional Precipitation Pogil Answer Key