1. 2KClO₃ xrightarrowΔ 2KCl + 3O₂ 2. Cr₂O₃ + 2Al xrightarrowΔ Al₂O₃ + 2Cr 3. Fe + 2HCl → FeCl₂ + H₂uparrow 4. 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂uparrow

Answer: 2. Cr₂O₃ + 2Al xrightarrowΔ Al₂O₃ + 2Cr Key idea: a metal displacement reaction is one where a more reactive metal displaces a less reactive metal from its compound. Cr₂O₃+2Al→ Al₂O₃+2Cr : Al displaces Cr from its oxide (aluminothermy). Option 1 and 4 are decompositions, and option 3 displaces hydrogen, not a metal.

Topic: Oxidation and reduction, oxidation number· Redox Reactions and Electrochemistry

Which of the following reactions is the metal displacement reaction ? Choose the right option.

1. \(2KClO_3 \xrightarrow{\Delta} 2KCl + 3O_2\)

2. \(Cr_2O_3 + 2Al \xrightarrow{\Delta} Al_2O_3 + 2Cr\)

3. \(Fe + 2HCl \rightarrow FeCl_2 + H_2\uparrow\)

4. \(2Pb(NO_3)_2 \rightarrow 2PbO + 4NO_2 + O_2\uparrow\)

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Answer: 2. \(Cr_2O_3 + 2Al \xrightarrow{\Delta} Al_2O_3 + 2Cr\)

Key idea: a metal displacement reaction is one where a more reactive metal displaces a less reactive metal from its compound.

\(\mathrm{Cr_2O_3+2Al\rightarrow Al_2O_3+2Cr}\): Al displaces Cr from its oxide (aluminothermy). Option 1 and 4 are decompositions, and option 3 displaces hydrogen, not a metal.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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Which of the following reactions is the metal displacement reaction ? Choose the right option.

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