Question

Which clue can be used to identify a chemical reaction as a replacement reaction?

The reaction has two reactants with ions that seem to switch places.
The reaction has a single reactant that changes into two or more products.
The reaction involves oxygen reacting with a hydrocarbon and giving off heat.
The reaction involves a single product forming from two or more reactants.

Answer 1

"The reaction has two reactants with ions that seem to switch places."

That's the clue for a replacement reaction (specifically a double‑replacement reaction).
- A single reactant → two or more products is decomposition.
- Oxygen + hydrocarbon with heat is combustion.
- One product from two or more reactants is synthesis (combination).