What is Acid rain and why does it occur?

Question

I am doing a school project so someone please help!!!

Answer 1

http://en.wikipedia.org/wiki/Acid_rain

All in one answer

Answer 2

Acid rain is any form of precipitation(rain, snow,sleet,fog, etc)which contains high levels of acid.Precisely,it is precipitation with dilute solutions of two strong acids--sulphuric and nitric.Both sulphur and nitrogen emissions are attributed to the burning of fossil fuels particularly high-sulphur coal and oil and particularly the use of the latter has increased due to industrial development.There has been a rise in carbon dioxide and sulphur and nitrogen oxides in the last 150 years during which fossil fuel consumption has increased.

In acid rain,which contains sulphuric acid,the first ingredient is the sulphur dioxide gas emitted by power stations,cars and lorries.When it meets the highly reactive chemical agents called OH radicals in the atmosphere,it is oxidised to form sulphur trioxide which is also a gas.This then combines with rain water to form sulphuric acid.

The pH value of pure rain water is about 7;but in the acid rain it becomes less than 4.In industrially advanced cities like Toronto and Los angels of the USA,the average pH value of rainfall becomes 3.5 and 2.2 respectively.