Competency #7
Answer and Explanation
Answer: By looking at the products (right of the arrow), you can predict the appearance of a precipitate- specifically, solid PbI2. This means the solutions will no longer be transparent, but will appear cloudy (because the of the solid particles suspended in the solution.) With time, or filtering, the solid particles will separate out from the aqueous layer.
As it happens, this reaction produces a brightly colored solid (the yellow color could not be predicted just from looking at the chemical equation).
| Pb(NO3)2 (aq) | + | 2KI (aq) |  |
PbI2 (s) + 2KNO3 (aq) |
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| Colorless, transparent solution | Colorless, transparent solution | Yellow solid PbI2, settling to the bottom of test tube. |
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