When an iron nail is immersed in a blue copper sulphate solution, the blue colour fades. This is mainly due to which ionic change?
Answer and explanation
Correct answer: The concentration of \(\mathrm{Cu^{2+}}\) ions in the solution decreases
The blue colour of copper sulphate solution is due to \(\mathrm{Cu^{2+}}\) ions. Since iron is more reactive than copper, it displaces copper in the reaction \(\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}\), depositing copper metal. Thus, the concentration of \(\mathrm{Cu^{2+}}\) ions decreases and the blue colour fades. In contrast, \(\mathrm{Fe^{2+}}\) ions are produced rather than decreased.
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What is the correct answer to this question?
The concentration of \(\mathrm{Cu^{2+}}\) ions in the solution decreases
Why is this the correct answer?
The blue colour of copper sulphate solution is due to \(\mathrm{Cu^{2+}}\) ions. Since iron is more reactive than copper, it displaces copper in the reaction \(\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}\), depositing copper metal. Thus, the concentration of \(\mathrm{Cu^{2+}}\) ions decreases and the blue colour fades. In contrast, \(\mathrm{Fe^{2+}}\) ions are produced rather than decreased.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
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