Metal Reactivity and Stability Assessment

Steps:

• Recall reactivity series: K > Na > Ca > Mg > Al > Zn > Fe > Sn > Pb > H > Cu > Ag > Au.
• Test displacement: Higher reactivity metal displaces lower one from solution.
• Evaluate acid reactions: Metals above H react with dilute acids to produce H2.
• Assess thermal stability: Carbonate stability increases down group 1; transition metal carbonates decompose more readily.

Why D is correct:

• Zinc, above copper in reactivity series, displaces Cu²⁺: Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s).

Why the others are wrong:

• A: Copper, below H, does not react with dilute HCl to form H₂.
• B: Sodium oxide requires electrolysis for reduction to Na; carbon reduces only less reactive metal oxides.
• C: Zinc carbonate decomposes on heating (less stable) unlike stable sodium carbonate.

Final answer: D