Fibers of the conducting polymer polypyrrole are woven into radar camouflage cloth. Because it absorbs microwaves, rather than reflecting them back to their source, the cloth appears to be a patch of empty space on radar.

(a) What is the hybridization of the N atom in polypyrrole?

(b) Explain why polypyrrole absorbs microwave radiation, but small organic molecules do not.
See Box 11E.1 for the structure of polypyrrole.

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Box 11E.1 FRONTIERS OF CHEMISTRY: CONDUCTING POLYMERS* One day, if you want to check your e-mail in a remote location, you might unroll a thin plastic sheet with a tiny microprocessor embedded in it. When you activate the microprocessor, your messages will appear and you might reply by touching it, writing on it with a special pen, or speaking to it. The remarkable mate- rial of this thin and flexible computer already exists: one form of it was discovered by accident in the early 1970s, when a chemist who was polymerizing ethyne (acetylene) added a thousand times too much catalyst. Instead of a synthetic rubber, he made a thin, flexible film. It looked like metal foil (see the photo- graph), and very much like a metal-it conducted electricity.* Metals conduct electricity because their valence electrons move easily from atom to atom. Most covalently bonded solids do not conduct electricity, because their valence electrons are locked into individual bonds and are not free to move. Exceptions such as graphite and carbon nanotubes have delocalized T-bonds