Question

Which reaction is a decomposition reaction? A. 2KClO3 → 2KCl + 3O2 B. 4Na + O2 → 2Na2O C. ZnS + 3O2 → 2ZnO + 2SO2 D. 2NaBr + CaF2 → 2NaF + CaBr2

Answer 1

Answer:

• Option A. 2KClO₃ → 2KCl + 3O₂

Explanation:

There are five basic general types of chemical reactions:

• Decomposition reactions

• Synthesis or combination reaction

• Single replacement reactions

• Double replacement reactions

• Combustion reactions

The given reactions are:

• 2KClO₃ → 2KCl + 3O₂

Which is, indeed, a decomposition reaction because the reactant, KClO₃, is a single substance that undergoes a reaction in which it yields two new substances, known as products: KCl and O₂.

• 4Na + O₂ → 2Na₂O is a synthesis or combination reaction because two reactants, Na and O₂, combine for the formation of one single new product, Na₂O.

• ZnS + 3 O₂ →  2ZnO + 2SO₂ is a single replacement reaction because oxygen is replacing Zn and S in ZnS to form ZnO and plus SO₂.

• 2NaBr + CaF₂ → 2NaF + CaBr₂ is a double replacement reaction because two  ions (Br⁻ from NaBr and F⁻ from CaF₂) are exchanging places with other two ions (Na⁺ from NaBr and Ca²⁺ from CaF₂) two form two new ionic compounds (NaF and CaBr₂).