Is rainwater a pure substance or a mixture?

1 Answer
Jul 4, 2017

rainwater can be considered a solution or a mixture.


Rain drops as they fall through the atmosphere will dissolve atmospheric gases. This makes rainwater a solution. All rainwater contains carbon dioxide # CO_2# In some extreme conditions rainwater can be a solution of sulfurous acid. #SO_2# dissolves into the raindrops forming an acidic solution.

Raindrops as they fall through the atmosphere can also absorb particles of dust and other material. In there is a lot of particular materials in the air the rainwater will become a mixture. The dust and other particles do not dissolve into the rainwater so it remains a mixture not a solution.