Chapter 9, Problem 84E

In the Chemistry and the Environment box on free radicals in this chapter, we discussed the importance of the hydroxyl radical in reacting with and eliminating many atmospheric pollutants. However, the hydroxyl radical does not clean up everything. For example, chlorofluorocarbons—which destroy stratospheric ozone—are not attacked by the hydroxyl radical. Consider the hypothetical reaction by which the hydroxyl radical might react with a chlorofluorocarbon:

OH(g)+ CF₂Cl₂(g)→HOF(g)+ CFCl₂(g)

Use bond energies to explain why this reaction is improbable. (The C—F bond energy is 552 kJ/mol.)