Balanced Single Displacement Reaction

Steps:

• Identify the reaction type: Magnesium displaces copper in copper(II) sulfate, a single displacement where a more reactive metal replaces a less reactive one.
• Write the skeleton equation: Mg + CuSO₄ → Cu + MgSO₄.
• Count atoms on both sides: Left has 1 Mg, 1 Cu, 1 S, 4 O; right matches exactly.
• Confirm balance: No coefficients needed as atoms are conserved.

Why A is correct:

• It obeys the law of conservation of mass with equal atoms of each element on both sides.

Why the others are wrong:

• B: Produces 2 Cu atoms on right but only 1 on left, violating atom balance.
• C: Requires 2 MgSO₄ but provides only 1 SO₄, unbalancing sulfur and oxygen.
• D: Yields 2 Cu but only 1 Cu source, and extra Mg without corresponding products.

Final answer: A