Anonymous
Sep 15
Butadiene shows absorption at a higher wavelength than ethene. Why?
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Sep 15
Butadiene has a longer conjugated system of double bonds compared to ethene. This longer conjugated system allows for more delocalization of electrons, resulting in absorption at a higher wavelength. Additionally, the presence of multiple double bonds in butadiene leads to a higher energy difference between the ground state and excited state, resulting in absorption at a higher wavelength.
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Google Gemini AI
Sep 15
Butadiene shows absorption at a higher wavelength than ethene due to the following reasons:
1. Conjugated Double Bonds: Butadiene contains two conjugated double bonds, meaning they are separated by a single bond. This conjugation allows for the delocalization of electrons, resulting in a more stable molecule.
2. Extended pi System: The conjugated double bonds create an extended pi system, which increases the number of molecular orbitals and decreases the energy difference between ground and excited states.
3. Reduced Energy Difference: The reduced energy difference between the ground and excited states means that less energy is required to excite the butadiene molecule, resulting in absorption at a higher wavelength (lower energy) compared to ethene.
4. Resonance: The conjugated double bonds in butadiene allow for resonance, which further stabilizes the molecule. Resonance contributes to the delocalization of electrons, reducing the overall energy of the butadiene molecule.
In contrast, ethene contains only one isolated double bond, so it has a smaller pi system, higher energy difference between electronic states, and less resonance stabilization. Therefore, ethene absorbs at a shorter wavelength (higher energy) than butadiene.
1. Conjugated Double Bonds: Butadiene contains two conjugated double bonds, meaning they are separated by a single bond. This conjugation allows for the delocalization of electrons, resulting in a more stable molecule.
2. Extended pi System: The conjugated double bonds create an extended pi system, which increases the number of molecular orbitals and decreases the energy difference between ground and excited states.
3. Reduced Energy Difference: The reduced energy difference between the ground and excited states means that less energy is required to excite the butadiene molecule, resulting in absorption at a higher wavelength (lower energy) compared to ethene.
4. Resonance: The conjugated double bonds in butadiene allow for resonance, which further stabilizes the molecule. Resonance contributes to the delocalization of electrons, reducing the overall energy of the butadiene molecule.
In contrast, ethene contains only one isolated double bond, so it has a smaller pi system, higher energy difference between electronic states, and less resonance stabilization. Therefore, ethene absorbs at a shorter wavelength (higher energy) than butadiene.
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