- A precipitate is an insoluble solid formed from a chemical reaction in a solution.
- Using solubility rules, lead(II) sulfate (\(PbSO_4\)) is identified as an insoluble compound.
- Magnesium chloride (\(MgCl_2\)) is identified as a soluble compound.
- Consequently, \(PbSO_4\) is the product that forms a precipitate.
- The final answer is \(\boxed{PbSO_4}\).
Explanation
- Analyzing Solubility of Products
A precipitate is an insoluble solid that forms during a chemical reaction when two solutions are mixed. The formation of a precipitate is governed by solubility rules, which describe whether various ionic compounds are soluble or insoluble in water. We evaluate each of the given products:
- \(PbSO_4\) (Lead(II) sulfate): Solubility rules indicate that while most sulfates are soluble, there are notable exceptions, including lead(II) sulfate (\(PbSO_4\)). Therefore, \(PbSO_4\) is insoluble and will form a precipitate when lead ions (\(Pb^{2+}\)) and sulfate ions (\(SO_4^{2-}\)) are present in a solution.
- \(MgCl_2\) (Magnesium chloride): Chloride salts are generally soluble. Magnesium chloride (\(MgCl_2\)) does not fall into the category of insoluble chlorides (which include silver, mercury, and lead(II) chlorides). Thus, \(MgCl_2\) remains in solution.
- \(PbMg\): This is an intermetallic alloy. It is not an ionic product expected from a typical aqueous double-displacement reaction and does not fit the definition of a precipitate in this context.
- "No precipitate formed": Since we have identified \(PbSO_4\) as an insoluble compound, this option is incorrect.
- Conclusion
Based on the analysis, \(PbSO_4\) is the only substance among the options that is insoluble in water and forms a solid precipitate when the corresponding ions are present. Thus, the correct product that forms a precipitate is \(PbSO_4\). Therefore, the final answer is \(\boxed{PbSO_4}\).
Examples
In environmental science, detecting heavy metals in wastewater is crucial for public safety. Chemists often use chemical precipitation to remove pollutants. For example, if wastewater contains lead ions, they might add a sulfate source to induce the precipitation of lead(II) sulfate, which can then be easily filtered out of the water to ensure the remaining liquid is cleaner and safer. Understanding solubility rules is a fundamental skill for environmental remediation and chemical engineering.