Passage I
The 4 common halide ions are fluoride (F-), chloride (C1-), bromide (Br-), and iodide (I-). A halide in solution can be identified by mixing the solution with various test solutions and observing the precipitates (solids), if any, that form.
Table 1 shows the results of mixing each of 4 colorless aqueous halide solutions with a colorless aqueous test solution containing calcium (Ca2+), silver (Ag+), thallium (T1+), or lead (Pb2+).
Table 2 shows the results of mixing each of 2 colorless aqueous solutions (A and B) with each test solution. Each of Solutions A and B is a combination of 2 of the halide solutions.
6. When each of the 4 halide solutions is mixed with the Ca2+ test solution, only 1 precipitate forms. This precipitate most likely has what chemical formula ?
Your Answer is
Correct Answer is H
Explanation
For the compound, it is ultimately uncharged. Ca2+ needs two electrons, and F- has only one electron, so the stable structure is CaF2 sub>