Question

10.What is the ozone layer?

11.What is happening to it? Why?

12.What are the effects?

13.What can we do? What have we done?

14.What is acid rain?

15.What causes it?

16.What effects does it have?

17.What can we do? What have we done?

Answer 1

10) Ozone layer

it's a region of the earth stratosphere which has high concentration of O₃ than the other parts of the atmosphere. It protects us from the harmful solar ultraviolent radiations.

In this layer of atmosphere ozone and oxygen atoms are contineously interconverted as solar UV radiation breaks ozone and then oxygen atoms reacts with another oxygen atom to form ozone again. ultra violet radiation breaks down O₂ to individual oxygen atom which reacts with O₂ to produce ozone.

O + O₂ <----> O₃

11) Depletion of ozone layer:

ozone layer is depleting in the stratosphere becasue of the release of large quantities of man-made organohalogen compounds like chloroflurocarbons(CFC) and bromofluorocarbons, volatile organic compounds are ozone depleting substances (ODS). CFCs are manufactured for their use in the process of refrigeration and styrofoam production. so, ODS are often found in vehicle emissions, byproducts of industrial processes, refrigerants and aerosols.

when the molecule of CFC (CFCl₃) is exposed to UV radiation a chlorine atom breaks away.

CFCl₃ + UV ------> CFCl₂ + Cl

This chlorine atom reacts with ozone and takes away one oxygen atom to make oxygen molecule.

O₃ + Cl -----> ClO + O₂

ClO + O₃ -----> ClO₂

ClO₂ -----> Cl + O_2......... (Cl atom free again to repeat the process )

this chlorine atom takes away oxygen atom from ozone molecules to make those into oxygen molecule and again free to repeat the process of converting ozone into oxygen molecule. oxygen molecule cannot stop UV rays entering the earth atmosphere like ozone. so these UV rays pass the atmosphere to reach earth surface at higher intensity.

12) Effects :

Depletion of ozone layer let harmful UV radiation to penetrate earth atmosphere. these radiations may cause serious skin problems like ageing and cancer and many others like depression of immune system.

so, The effects of UV radiations on Human are eye defects like eye cataracts, weakened immune system, skin cancer, sunburn and mutagenesis( change in the genetic information of the organism).

On nature it causes crop damage, destruction of plants , increase in global warming.

13) we should not use old air conditioners or old refrigerators, spray cans fire extinguishers etc which are the source of harmful CFC.

we should reduce use of vehicles and avoid industrial products as much as we can and start to go for more organic things.

strict laws to prevent release of harmful gases in the atmosphere should be implemented. so that use of certified gases can be strictly used in industrial productions.

14) Acid rain : It's a form of precipitation with acidic components. so it has higher level of Hydrogen ions or has low pH.

15) Acid rain is caused by high emission of sulfur dioxide and nitrogen dioxide.
These molecules react with water in the atmosphere to produce acids such as sulfuric acid and nitric acid.
In the atmosphere carbondioxide react with water to produce carbonic acid which precipitate with rain.
even when there is no pollution rain is little acidic in nature, but very mildly.
so mostly prime cause of acid rain is emission of sulfur and nitrogen compounds. and the sources are electricity generation plants, factories and motor vehicles.

16) the effects of acid rains are:
a) adverse impact of forests and soil, b) destroy insects and aquatic lifeforms, c) impact of human health, d) damage buildings.
change is pH kills many micro-organisms which are essential for healthy soil. also these acids wash away many nutrients of the soil suchas magnesium.
This make the soil less favourable for plants and so affects the forest aswell.   
In ocean corals are sensitive to the pH of the water and when pH level changes adverse effects can be seen on it.
lime stone and marbel structures which contain calcium carbonate and acid in the rain reacts with it to cause damage.

17)Since most of the gases which cause acid rain emits from power plants, so we need clean energy sources.
Vehicles are another source of nitrogen oxides, so vehicle emission control can reduce the emission.
Lesser use of vehicles should be prefered. or clean way for transportation should be prefered.
factories should be checked and encouraged to take pollution preventive measures.