how is chemistry in rain?

Answer 1

The individual drops of rain usually form as pure drops of water. As these drops fall, they encounter gases in the atmosphere which can be absorbed and react with the water.

Most of the gases are oxides of nonmetal elements. When they react with water, they form acids. This is the source of "acid rain."

For example Nitrogen dioxide reacts with water to form nitric acid.

Answer 2

Rain is not pure water, so there is plenty of chemistry in rain.

Answer 3

H2O