- Analyze the reactants and identify the ions present: \(Pb^{2+}\), \(Cl^-\), \(Mg^{2+}\), and \(SO_4^{2-}\).
- Perform a double displacement swap where cations pair with the new anions: \(Pb^{2+}\) with \(SO_4^{2-}\) and \(Mg^{2+}\) with \(Cl^-\).
- Balance the ionic charges to establish correct chemical formulas: \(PbSO_4\) and \(MgCl_2\).
- Select the matching set of products from the given options, confirming that \(PbSO_4 + MgCl_2\) is the correct outcome.
- The correct products for the reaction are \(\boxed{PbSO_4 + MgCl_2}\).
Explanation
- Analysis of the Chemical Reaction
A double replacement reaction, also known as a metathesis reaction, occurs when two ionic compounds in aqueous solution exchange their ions to form new compounds. The general equation for this reaction is \(AB + CD \rightarrow AD + CB\). In our case, the reactants are lead(II) chloride (\(PbCl_2\)) and magnesium sulfate (\(MgSO_4\)). The constituent ions are:
- Lead(II) chloride: Lead(II) ion (\(Pb^{2+}\)) and chloride ion (\(Cl^-\)).
- Magnesium sulfate: Magnesium ion (\(Mg^{2+}\)) and sulfate ion (\(SO_4^{2-}\)).
- Determining the Products and Balancing Formulas
To find the products, we swap the cations and anions of the reactants. The lead(II) ion (\(Pb^{2+}\)) pairs with the sulfate ion (\(SO_4^{2-}\)) to form lead(II) sulfate (\(PbSO_4\)). The magnesium ion (\(Mg^{2+}\)) pairs with the chloride ion (\(Cl^-\)) to form magnesium chloride (\(MgCl_2\)). We must ensure the chemical formulas are balanced based on the ionic charges. Lead(II) (\(Pb^{2+}\)) and sulfate (\(SO_4^{2-}\)) have a 1:1 ratio because the charges cancel each other out (\(+2 + -2 = 0\)). Magnesium (\(Mg^{2+}\)) has a +2 charge and chloride (\(Cl^-\)) has a -1 charge, so it takes two chloride ions to balance one magnesium ion, resulting in the formula \(MgCl_2\). Thus, the complete reaction is \(PbCl_2 + MgSO_4 \rightarrow PbSO_4 + MgCl_2\).
- Identifying the Correct Products
Comparing our balanced equation with the provided options:
- \(Pb + O_2 + MgCl\)
- \(PbMg + ClSO_4\)
- \(PbSO_4 + MgCl_2\)
- \(Pb(SO_4)_2 + MgCl\)
The correct set of products is \(PbSO_4 + MgCl_2\), which corresponds to the third option. Therefore, the products of the double replacement reaction are lead(II) sulfate and magnesium chloride.
Examples
Precipitation reactions, such as the one described here, are essential in various fields, including environmental science and water treatment. For example, if you wanted to remove harmful lead ions from contaminated water, you could add a source of sulfate ions (like magnesium sulfate). This reacts with the lead ions to form lead(II) sulfate, which is highly insoluble and forms a solid precipitate that can be filtered out, effectively purifying the water. Understanding how to predict these reactions allows scientists to develop methods for remediation and chemical safety in everyday environments.