Which of the following reaction liberates maximum amount of heat energy?

Options

A.
B.
C.
D.

Explanation

To determine which reaction liberates the maximum amount of heat energy, we need to analyze the heat of hydrogenation for the given compounds. The heat of hydrogenation is the amount of heat released when an alkene is converted to an alkane through the addition of hydrogen.

### Step-by-Step Solution:

1. **Identify the Reactions**:
- Look at the given options, which likely include various alkenes and cycloalkanes.

2. **Understand Heat of Hydrogenation**:
- The heat of hydrogenation is generally higher for less substituted alkenes. This is because less substituted alkenes are less stable and release more energy when they are hydrogenated to form alkanes.

3. **Analyze Substituents**:
- For each alkene in the options, identify the number of substituents (alkyl groups) attached to the double bond. The more substituents an alkene has, the more stable it is, and the less heat is released during hydrogenation.

4. **Compare the Options**:
- Compare the substituents of each alkene:
- The alkene with the least number of substituents will liberate the maximum amount of heat upon hydrogenation.
- For example, if you have an alkene with no substituents (like ethylene) versus one with two methyl groups (like 1,2-dimethylpropene), the former will release more heat.

5. **Select the Reaction**:
- Based on the analysis, select the reaction that corresponds to the least substituted alkene. This reaction will liberate the maximum amount of heat energy.

### Conclusion:
- The reaction that liberates the maximum amount of heat energy is the one involving the least substituted alkene.