Consider the following balanced chemical equation: 2 Al (s) + 3 CuCl2 (aq) —> 2 AlCl3 (aq) + 3 Cu (s) Which of the following statements best describes what is occurring during this reaction? A. Aluminum ions are replacing copper atoms from the solution. B. Aluminum atoms are replacing copper ions from the solution. C. Copper atoms are replacing aluminum ions from the solution. D. Copper ions are replacing aluminum atoms from the solution.
The Correct Answer and Explanation is:
Correct Answer: B. Aluminum atoms are replacing copper ions from the solution.
Explanation:
In the given chemical reaction:
2 Al (s) + 3 CuCl₂ (aq) → 2 AlCl₃ (aq) + 3 Cu (s)
The reaction involves solid aluminum metal reacting with an aqueous solution of copper(II) chloride. To understand the process, consider the nature of each substance:
- Al (s) represents elemental aluminum in solid form.
- CuCl₂ (aq) contains copper(II) ions (Cu²⁺) and chloride ions (Cl⁻) dissolved in water.
- AlCl₃ (aq) is aluminum chloride, which dissociates into aluminum ions (Al³⁺) and chloride ions in aqueous solution.
- Cu (s) is elemental copper, appearing as a solid.
This is a single displacement reaction, also known as a redox reaction. In such reactions, a more reactive metal displaces a less reactive metal from its compound.
In this case, aluminum, being more reactive than copper, displaces copper ions from the aqueous copper(II) chloride solution. The aluminum atoms lose electrons and form aluminum ions:
Al (s) → Al³⁺ (aq) + 3e⁻
Simultaneously, the copper ions in the solution gain these electrons and become solid copper atoms:
Cu²⁺ (aq) + 2e⁻ → Cu (s)
The overall transformation shows that aluminum atoms are oxidized to aluminum ions, and copper ions are reduced to copper metal. This exchange of electrons marks the redox process.
Thus, during the reaction, aluminum atoms replace copper ions in the solution, resulting in the formation of aluminum chloride in solution and solid copper as a product. This clearly supports option B as the most accurate description of the process.
