Question

How many pi bonds are present in caffeine ?

Answer 1

The caffeine molecule has $$4$$ pi bonds.

Every time you are asked to determine the number of pi or sigma bonds in a compound, you must draw its Lewis Structure.

Here's how the caffeine molecule looks like:

The important thing to remember is that double bonds are comprised of $$1$$ sigma bond and $$1$$ pi bond and triple bonds are comprised of $$1$$ sigma bond and $$2$$ pi bonds.

Caffeine's Lewis structure shows that no triple bonds are present; however, four double bonds are, which means that the number of pi bonds in a caffeine molecule is equal to $$4$$.

By comparison, caffeine has $$25$$ sigma bonds.