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Problem 15 - Entrance Test

Which of the following is an example of a combination reaction?

Correct: B

A combination reaction (also known as a synthesis reaction) is a reaction in which two or more reactants combine to form a single, more complex product. - A) CaCO₃(s) → CaO(s) + CO₂(g) is a decomposition reaction. - B) 2Mg(s) + O₂(g) → 2MgO(s): Magnesium combines with oxygen to form magnesium oxide. This fits the definition of a combination reaction. - C) Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s) is a displacement reaction. - D) BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq) is a double displacement reaction.