Using the bond-dissociation energies in Table 5.6, (a) predict whether or not a fluorine radical would be selective for forming a single radical from propane.

Verified step by step guidance

1. Step 1: Understand the concept of bond-dissociation energy. It is the energy required to break a bond in a molecule into two radicals. The higher the bond-dissociation energy, the stronger the bond.
2. Step 2: Look up the bond-dissociation energies for the C-H bond in propane and the C-F bond that would be formed. The bond-dissociation energy for the C-H bond in propane is typically around 410 kJ/mol, while the bond-dissociation energy for the C-F bond is typically around 485 kJ/mol.
3. Step 3: Compare these energies. If the energy of the C-F bond is higher than the energy of the C-H bond, then the fluorine radical would be selective for forming a single radical from propane. This is because the formation of the C-F bond would release more energy than the breaking of the C-H bond, making the reaction exothermic and therefore favorable.
4. Step 4: Consider other factors that might affect the selectivity of the fluorine radical. For example, the size and electronegativity of the fluorine atom might make it more likely to react with certain parts of the propane molecule.
5. Step 5: Based on these considerations, make a prediction about whether or not the fluorine radical would be selective for forming a single radical from propane.

Key Concepts

Bond Dissociation Energy

Bond dissociation energy (BDE) is the energy required to break a specific bond in a molecule, resulting in the formation of radicals. It is a crucial concept in predicting the stability of radicals and the likelihood of certain reactions occurring. Higher BDE values indicate stronger bonds, making them less likely to break, while lower values suggest weaker bonds that are more susceptible to cleavage.

Radical Selectivity

Radical selectivity refers to the preference of a radical species to react with certain substrates over others, often influenced by the stability of the resulting radical. In the case of fluorine radicals, their high reactivity can lead to non-selective reactions, but understanding the stability of potential products helps predict whether a selective reaction will occur. This concept is essential for evaluating reaction pathways in organic chemistry.

Propane Structure and Reactivity

Propane is a three-carbon alkane with a simple structure that can undergo radical reactions, particularly in the presence of halogens like fluorine. The reactivity of propane is influenced by the presence of primary, secondary, and tertiary hydrogen atoms, which differ in their bond strengths and the stability of the resulting radicals. Understanding the structure of propane is vital for predicting how it will react with a fluorine radical.