26 Maret 2012


This written is just inspired by the question of a child to me. That night, I was teaching him. His mother who just came from her office told me about acid rain. Her child asked to me,

“What is the acid rain?”

Hey, I was a little confused with that question while I’m a bacelor on chemistry major!

Actually, acid rain is same of usual rain, but its different is the acidity. In usual rain, the acidity is average of pH 6, while in acid raining can increas to ph 4,5-5,5. Why it can be acid? In usual raining, acidity is caused by solving CO2 from the air to the rain. It is a weak acid compound and it needed to solving minerals from the soil that used by plants and animals.

While in acid rain, acidity is caused by two compounds, they are nitrogen and sulphur. By its source, there is two sources that can cause the acid rain. First, nature source such as from eruption of flaming mountain and a lot of biology activities that is in the soil, swamp, or sea. Second, from the human activities, either deliberate or not. For example on power station, farmation industries, or agricultural industries, especially that use amonia compound.

The process of acid rain is reaction of sulphur and nitrogen that escape to the air, with oxygen. This reaction produces compounds such as sulphur dioxide and nitrogen oxide. Both of them are diffuse to the atmosphere especially to the tropospher, then reacts with H2O and produce sulphate acid and nitrate acid.

Chemical reaction of acid rain is:
S(s) + O2(g) --> SO2(g)
2SO2(g) + O2(g) --> SO3(g)
SO3(g) + H2O(l) --> H2SO4(aq)

Both acid sulphate and nitrate acid are strong acid which solve in the water. It causes that compounds solve in the rain.

So what is the danger of acid rain?

For the plants, acid rain is causes the death of them. It’s caused by the heigth of SO2 that can wreck wax coat of the leaf so its nutrition is lost. For the effect, plants is not resistent from the low term, fungus, and insects. Besides, the low Ph also causes decrease of magnesium by process of washing magnesium in the soil.  

Acid rain that falls to the lake or surface of soil can causes increasing acidity in the soil and water surface. The fish can’t live in the low acidity water. Acid also chain the poison metal such as alumunium in the lake. Aluminium causes some fishes produce mucus more than usual around the gill so the fishes will dificult to breath. The growth of Phytoplankton as a food source of fish is blocked by the heigth of pH.

The other effect of acid rain is released out of poison ions, either to the air and to water. Ion such as copper can cause diarrhoea, and alumunium that staining water can cause alzheimer syndrome.

From the description above, it would be good to us to posturing all of industry activities, especially that use the hazardous chemical compounds.

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