Identify the type of each of the following reactions, stating the reason for your answers.
A. [tex]Fe _2 O _3+2 Al \rightarrow Al _2 O _3+2 Fe +[/tex] heat
B. [tex]Pb \left( NO _3\right)_2+2 KI \rightarrow PbI _2(\downarrow)+2 KNO _3[/tex]
Answer (2)
Reaction A is a single replacement reaction because aluminum replaces iron in iron oxide.
Reaction B is a double replacement reaction because lead and potassium ions switch places, forming lead iodide precipitate.
Reaction A is a single replacement.
Reaction B is a double replacement.
Explanation
Problem Analysis We are given two chemical reactions and asked to identify the type of each reaction, providing a reason for our answers.
Analyzing Reaction A Reaction A: F e 2 O 3 + 2 A l → A l 2 O 3 + 2 F e + heat
Identifying Reaction A In reaction A, we observe that aluminum (Al) replaces iron (Fe) in iron oxide ( F e 2 O 3 ). This indicates a single replacement reaction. The presence of 'heat' as a product signifies that the reaction is exothermic.
Analyzing Reaction B Reaction B: P b ( N O 3 ) 2 + 2 K I → P b I 2 ( ↓ ) + 2 K N O 3
Identifying Reaction B In reaction B, we see that lead ( P b 2 + ) and potassium ( K + ) ions switch places between the reactants. Specifically, lead combines with iodide to form lead iodide ( P b I 2 ), which is a precipitate (indicated by the downward arrow ↓ ). Potassium combines with nitrate to form potassium nitrate ( K N O 3 ). This is a characteristic of a double replacement reaction.
Conclusion Therefore, reaction A is a single replacement reaction, and reaction B is a double replacement reaction.
Examples
Understanding reaction types is crucial in various fields. For instance, in environmental science, knowing whether a reaction is a single or double replacement can help predict the products of pollutants interacting in water or soil. In materials science, identifying exothermic reactions is essential for designing safe and efficient processes for synthesizing new materials. In everyday life, understanding these reactions helps us comprehend how batteries work (redox reactions) or how baking soda neutralizes acids (acid-base reactions).
In reaction A, aluminum replaces iron in iron oxide, making it a single replacement reaction. In reaction B, lead and potassium ions switch places, resulting in a double replacement reaction. Thus, Reaction A is a single replacement and Reaction B is a double replacement.
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