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.

Explanation:

To identify a replacement reaction (specifically double - replacement, a common type), we analyze each option:

• Option 1: In a double - replacement reaction, the general form is \(AB + CD

ightarrow AD+CB\), where the ions (or parts of the compounds) switch places. So if a reaction has two reactants with ions that switch places, it is a replacement reaction.

• Option 2: A reaction with a single reactant that breaks into two or more products is a decomposition reaction (e.g., \(2H_2O_2

ightarrow2H_2O + O_2\)).

• Option 3: A reaction where oxygen reacts with a hydrocarbon and gives off heat is a combustion reaction (e.g., \(CH_4+2O_2

ightarrow CO_2 + 2H_2O\)).

• Option 4: A reaction with two or more reactants forming a single product is a synthesis reaction (e.g., \(H_2+O_2

ightarrow H_2O\) (balanced as \(2H_2 + O_2
ightarrow2H_2O\))).

Answer:

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