Question

A decomposition reaction is the opposite of which of the following reaction?
1. Combination reaction
2. Thermal decomposition
3. Displacement reaction
4. Double displacement reaction

Answer 1

Correct Answer - Option 1 : Combination reaction

The correct answer is 1 i.e. Composition reactions.

Decomposition reaction:

• Those reactions in which a compound splits up into two or more simpler substances are known as decomposition reactions.
• The decomposition reactions are carried out by applying heat, light or electricity.
• Heat, light, or electricity provide energy that breaks a compound into two or more simpler compounds. 
• A decomposition reaction is the opposite of a combination reaction. 
• Thermal decomposition:
  • ​When a decomposition reaction is carried out by heating, it is called 'thermal decomposition'.
  • The decomposition reaction of calcium carbonate into calcium oxide and carbon dioxide is an example of thermal decomposition.
• Example:
  • ​2FeSO4 → Fe2O3 + SO2 + SO3