Select the correct answer. Based on the reactivities of the elements involved, which reaction will form products that are more stable than the reactants?
A. [tex]2 AlBr _3+3 Zn \rightarrow 3 ZnBr _2+2 Al[/tex]
B. [tex]CaBr _2+2 Na \rightarrow 2 NaBr + Ca[/tex]
C. [tex]MgBr _2+ H _2 \rightarrow 2 HBr + Mg[/tex]
D. [tex]BaBr _2+ Ca \rightarrow CaBr _2+ Ba[/tex]
E. [tex]2 LiBr + Ba \rightarrow BaBr _2+2 Li[/tex]
Answer (2)
Determine the relative reactivity of the elements in each reaction using the activity series.
Identify the reaction where a more reactive element displaces a less reactive element.
Check if the products formed are more stable than the reactants based on the activity series.
Conclude that reaction E, 2 L i B r + B a → B a B r 2 + 2 L i , forms products that are more stable than the reactants, since Li is more reactive than Ba.
The final answer is E.
Explanation
Understanding the Problem and Activity Series We are looking for a reaction where the products are more stable than the reactants. This occurs when a more reactive element displaces a less reactive element in a compound. We will use the activity series to determine the relative reactivity of the elements in each reaction. The activity series is (from most to least reactive): Li > Ba > Ca > Na > Mg > Al > Zn > H.
Analyzing Option A A. 2 A lB r 3 + 3 Z ni g h t ha r p oo n u p 3 Z n B r 2 + 2 A l : Zinc (Zn) should be more reactive than Aluminum (Al) for the products to be more stable. According to the activity series, Al is more reactive than Zn, so the reactants are more stable.
Analyzing Option B B. C a B r 2 + 2 N ai g h t ha r p oo n u p 2 N a B r + C a : Sodium (Na) should be more reactive than Calcium (Ca) for the products to be more stable. According to the activity series, Na is less reactive than Ca, so the reactants are more stable.
Analyzing Option C C. M g B r 2 + H 2 i g h t ha r p oo n u p 2 H B r + M g : Hydrogen (H) should be more reactive than Magnesium (Mg) for the products to be more stable. According to the activity series, Mg is more reactive than H, so the reactants are more stable.
Analyzing Option D D. B a B r 2 + C ai g h t ha r p oo n u pC a B r 2 + B a : Calcium (Ca) should be more reactive than Barium (Ba) for the products to be more stable. According to the activity series, Ba is more reactive than Ca, so the reactants are more stable.
Analyzing Option E E. 2 L i B r + B ai g h t ha r p oo n u pB a B r 2 + 2 L i : Barium (Ba) should be more reactive than Lithium (Li) for the products to be more stable. According to the activity series, Li is more reactive than Ba, so the reactants are less stable and the products are more stable.
Conclusion Based on the analysis, reaction E will form products that are more stable than the reactants.
Examples
In metal displacement reactions, a more reactive metal will displace a less reactive metal from its salt solution. This principle is used in various industrial processes, such as extracting metals from their ores. For example, copper can be extracted from copper sulfate solution by adding iron, as iron is more reactive than copper: C u S O 4 + F e → F e S O 4 + C u . This concept is also crucial in understanding corrosion, where more reactive metals corrode preferentially to protect less reactive ones.
Based on the analysis of the reactivities in the reactions, option E, 2 LiBr + Ba → BaBr 2 + 2 Li , is the correct choice as it produces more stable products due to the higher reactivity of Lithium compared to Barium.
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