The enthalpy of hydrogenation for 1-pentene is +126 kJ/mol. The enthalpy of hydrogenation for 1, 3-pentadiene is +230 kJ/mole. Hence estimate the resonance energy of 1, 3-pentadiene.

Options

A. `-22 kJ`
B. `-104 kJ`
C. `-252 kJ`
D. Cannot be calculated from this information

Explanation

To estimate the resonance energy of 1,3-pentadiene based on the given enthalpy of hydrogenation values, we can follow these steps:

### Step 1: Understand the Enthalpy of Hydrogenation
The enthalpy of hydrogenation is the heat change that occurs when an alkene is hydrogenated to form an alkane. For 1-pentene, the enthalpy of hydrogenation is given as +126 kJ/mol. This means that converting 1-pentene to pentane releases energy, and the value indicates how much energy is absorbed during the process.

### Step 2: Calculate the Expected Enthalpy of Hydrogenation for 1,3-Pentadiene
1,3-Pentadiene has two double bonds. If we assume that each double bond has the same enthalpy of hydrogenation as 1-pentene, we can calculate the expected enthalpy of hydrogenation for 1,3-pentadiene as follows:

\[ \text{Expected Enthalpy for 1,3-Pentadiene} = 2 \times \text{Enthalpy of Hydrogenation for 1-Pentene} \]
\[ = 2 \times 126 \text{ kJ/mol} = 252 \text{ kJ/mol} \]

### Step 3: Compare the Expected and Observed Enthalpy of Hydrogenation
The observed enthalpy of hydrogenation for 1,3-pentadiene is given as +230 kJ/mol.

### Step 4: Calculate the Resonance Energy
The resonance energy can be calculated using the formula:

\[ \text{Resonance Energy} = \text{Observed Enthalpy} - \text{Calculated Enthalpy} \]
Substituting the values we have:

\[ \text{Resonance Energy} = 230 \text{ kJ/mol} - 252 \text{ kJ/mol} = -22 \text{ kJ/mol} \]

### Conclusion
The estimated resonance energy of 1,3-pentadiene is -22 kJ/mol.