ACID RAIN

Acid Rain : Causes & Effects

Many times in a day you come across mixtures,for instance you start your day by taking a cup of tea at break fast,tea is a mixture,it is composed of water,milk,tea leaves,and sugar,or if you take milk instead of tea ,it also is a mixture of water,minerals,proteins,vitamins and fats.You also know that if some mud is added to this cup of tea ,the tea does not remain fit for drinking.If you drink you will fell ill.In the same way air is a mixture of various gases like nitrogen,oxygen,hydrogen,carbon dioxide,noble gases and water vapors. Now you will learn from this article how the atmosphere gets polluted etc 

Planet earth -our home was formed about 4.6 million years ago from a mass of particles swirling around the sun.It is surrounded by a thick blanket of gas,the atmosphere,and mostly covered by water.The earth rotates around its axis once in every 24 hours and orbits the sun continuously.From space the earth looks beautiful and unchanging .However zoom in closer and thing are very different.The planet is teeming with life.Hundreds of thousands of different species including 7.5 billion human beings live here.Every living thing depend on ,and interact with,the atmosphere,rocks,oceans,and other living things in some way.However, human interact more than other organisms.They have the intelligence to change the environment to suit their needs.In doing so,human have put the planets at the risk.Exploitation of natural resources does not have immediate effects,but may have long term and irreversible consequences in years to come.    

Acid Rain :

The atmosphere contains carbon dioxide from natural source such as respiration.This dissolves in rain water forming a weak acid rain.However the increased burning of fossil fuels all over the world has increased the acidity of the rain.This is because burning fossil fuels produces Sulphur dioxide. Sulphur dioxide dissolves in water to produce sulphuric acid which is a strong acid. Sulphur dioxide is released into the air when fossil fuels are burned at power.

Effects on Environment

Acid rain damages statues and buildings made of lime stone or marble (calcium carbonate).It attacks the cement that holds the buildings together.It also corrodes metals,weakening structure made of them.Acid rain makes lakes acidic.This has a serious effect on the ecosystem.The acid causes aluminium to be released from the soil into the water.Aluminium is poisonous to aquatic life.It kills fish and the birds that eat them.Acid rain causes the death of trees and other plants.Their leaves drop off and their roots are damaged so they cannot absorb water. 

Many modern power stations that burn fossil fuels have scrubbers which remove the harmful gases from the smoke.In many countries modern cars,lorries,buses,and trains are fitted with'' catalytic converters '' to clean exhaust gases.

Causes of Acid Rain

It has been proved that when two main gases sulphur dioxide and nitrogen oxide are emitted into air atmosphere,this is the major cause of acid rain.It is further transported by air in whole of the atmosphere.The sulphur dioxide and nitrogen oxide both react with water,as a result of this reaction oxygen and other chemicals give sulphuric acid and nitric acid respectively.These further mix with water and other materials before falling to ground.The less amount of aforesaid gases both sulphur dioxide and nitrogen oxide which is the vital factor behind the acid rain is obtained from natural resources like volcanoes but prominent source is burning of fossil fuels.Its main sources are appended below.

(a)--- 2/3 of sulphur dioxide and 1/4 of NO in atmosphere are generated from electric power           generators.

(b)--- next is the mechanical transport vehicles and heavy equipment

(c)--- Oil refineries along with industries and factories etc

(d)----Wind can blow both SO2 and NO

Incineration :

It is a wast treatment process in which solid wast is burned at high temperature .Incineration consumes all combustible materials,leaving behind ash residue and non combustible materials.This process generally reduces volume of wast by two third,but it not a clean process.It produces air pollution.It generates considerable smokes and odor .This smoke may contain oxides of nitrogen and sulphur. 

Conclusion:

Normal rain water is saturated with carbon dioxide.It has PH of 5.6 however,the acidity of rain greatly increases in polluted areas during thunder storm .Sulphur dioxide from power plants using fossil fuels and nitrogen oxides from exhaust fumes of automobiles dissolve in rain water producing acids.Therefore,during thunderstorm ,the PH of the rain water can be much lower because of sulphuric acid and nitric acid formed by lightening .This rain may have PH as low as 2.1.This value lower than PH of vinegar or lemon juice.Acid rain may often fall hundreds of kilometers away from their sources.Acid rain corrodes metals,stone buildings and statues .Sulphuric acids eat away metals to form water soluble salt and hydrogen.Marble buildings and statues are disintegrated by acid rain.Acid rain also kills fish and destroys trees,lakes and rivers may become too acidic for living things to survive