Balanced Single Displacement Reaction

Steps:

• Identify reactants: Magnesium (Mg) displaces copper(II) from CuSO₄(aq).
• Write unbalanced equation: Mg + CuSO₄ → Cu + MgSO₄.
• Balance atoms: One Mg, one Cu, one S, four O on both sides—no coefficients needed.
• Confirm states: Aqueous CuSO₄ and MgSO₄, solid Cu, but equation focuses on formulas.

Why A is correct:

• It is the balanced molecular equation per conservation of mass, with equal atoms on both sides.

Why the others are wrong:

• B: Identical to A, but listed separately—likely a duplicate error.
• C: Overuses Mg (two atoms) without balancing products, violating atom conservation.
• D: Doubles Mg but leaves one Cu and one MgSO₄, unbalancing sulfate and magnesium ions.

Final answer: A