In which example does a colour change occur along with the formation of new substances?
Answer and explanation
Correct answer: Placing an iron nail in copper sulphate solution
When an iron nail is placed in blue copper sulphate solution, iron displaces copper from copper sulphate. Green iron sulphate and copper are formed: \(\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}\). Thus, the colour change is accompanied by the formation of new substances. In contrast, folding paper is only a physical change and produces no new substance.
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What is the correct answer to this question?
Placing an iron nail in copper sulphate solution
Why is this the correct answer?
When an iron nail is placed in blue copper sulphate solution, iron displaces copper from copper sulphate. Green iron sulphate and copper are formed: \(\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}\). Thus, the colour change is accompanied by the formation of new substances. In contrast, folding paper is only a physical change and produces no new substance.
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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