Acid rain is any type of precipitation with acidic components that falls to the ground from the atmosphere. They are mainly two types:- (a) Wet Deposition. (b) Dry Deposition

  • Wet Deposition:- This type of deposition includes rain, fog and snow.
  • Dry Deposition:- Dry deposition is another form of acid deposition and this is when gases and dust particles become acidic.
     
The normal rain is mildly acidic showing pH value of around 6. This mild acidity is due to dissolution of C02 that forms carbonate acid.

    H2O     +          CO2       ⇄                H2CO3
(Water)  (carbon dioxide) (carbonic acid)

Cause of acid rain:-  They are two cause of acid rain.
(a) Natural causes
(b) Human activity.

  • Natural Causes:- (a) Rotting vegetation    (b) Eruption volcano.
  • Human activity:-  (a) Industry  (b) Traffic  (c) Electricity
Acid rain is caused by chemical reaction that begins when compounds like sulfur dioxide and nitrogen are released into the air. These substance can raise very high into atmosphere where they mix and react with water, oxygen and other chemical to form more pollutants known as acid rain. Sulfur dioxide and nitrogen dioxide dissolved very easily in water and can be carried very far by the wind.

    2S02 (g)      +     02(g)     →        SO3(g)  (Sulfur dioxide)(oxygen)(sulfur trioxide)

    SO3(g)       +    H2O(l)    →     H2SO4(aq)
(Sulfur trioxide) (Water)    (Sulfuric acid)

  NOx            +      H2O       →        HNO3
(Nitrogen oxids) (Water)   (Nitric acid)

Adverse effects of acid rain :-

  1. Effect of acid rain in human being:-
  2. Effect of acid rain on building material:-