Which reaction below represents a decomposition reaction? (A decomposition reaction is where a single reactant breaks down into two or more products.)

A) 2H2 + O2 → 2H2O

B) NaCl + AgNO3 → NaNO3 + AgCl
C) C6H12O6 → 2C2H6O + 2CO2
D) H2O + CO2 → H2CO3

To identify a decomposition reaction, we need to look for a reaction where a single reactant breaks down into two or more products. Let's examine the options provided and determine which one represents a decomposition reaction.

Option 1: AB → A + B
Option 2: A + B → AB
Option 3: ABC → AB + C
Option 4: AB + C → AC + B

In decomposition reactions, the reactant breaks down into smaller parts.

Looking at the options, we can see that only option 3 (ABC → AB + C) represents a decomposition reaction. In this reaction, the reactant ABC breaks down into products AB and C. Therefore, the correct answer is option 3: ABC → AB + C.

A decomposition reaction can be represented by the reaction equation:

AB ⟶ A + B

In this reaction, the compound AB breaks down into its individual elements A and B.