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Showing 2 questions in Chemistry for Class 10. Tap a card to reveal the answer.
ChemistryChemical Reactions and EquationseasyWhen an iron nail is dipped in copper sulphate solution, the blue colour fades. Write the reaction and name its type.
Reveal answer ↓
What it is
A more reactive metal displaces a less reactive one from its salt solution.
Answer
Iron is more reactive than copper, so it displaces copper from copper sulphate: Fe + CuSO4 -> FeSO4 + Cu. The blue colour of CuSO4 fades as it is replaced by the pale green FeSO4, and a brown copper coating forms on the nail. This is a displacement reaction.
Fe + CuSO4 -> FeSO4 + Cu
- •Fe + CuSO4 -> FeSO4 + Cu
- •More reactive metal displaces less reactive one
- •Blue fades, brown Cu deposits
- •Type: displacement (also redox)
Why learn this
It explains rust protection, how metals are extracted and why copper salt is not stored in iron pots.
💡 Memory trick
Higher in the reactivity series pushes the lower one OUT (displacement).
ChemistryChemical Reactions and EquationsmediumIn the reaction CuO + H2 -> Cu + H2O, identify the substance oxidised and the substance reduced.
Reveal answer ↓
What it is
In a redox reaction one substance gains oxygen (oxidised) while another loses it (reduced), together.
Answer
Hydrogen gains oxygen to form water, so H2 is oxidised. Copper oxide loses oxygen to form copper, so CuO is reduced. Since oxidation and reduction happen together, this is a redox reaction; here H2 acts as the reducing agent and CuO as the oxidising agent.
CuO + H2 -> Cu + H2O
- •H2 gains oxygen -> oxidised (reducing agent)
- •CuO loses oxygen -> reduced (oxidising agent)
- •Oxidation and reduction occur together = redox
Why learn this
Redox runs respiration, rusting, batteries and photosynthesis - energy in and out of everything.
💡 Memory trick
OIL RIG: Oxidation Is Loss, Reduction Is Gain (of oxygen or electrons).