Chemistry M.C.Q (1 Marks)

As the altitude increases, the pressure decreases which results in thinning of the earth's atmosphere.

The photochemical smog is formed by the reaction of solar radiation with airborne pollutants like nitrogen oxides and volatile organic compounds. These compounds are called primary pollutants. Ultraviolet light can split nitrogen dioxide into nitric oxide and monatomic oxygen; this monatomic oxygen can then react with oxygen gas to form ozone. Products like ozone, aldehydes, and peroxyacetyl nitrates are called secondary pollutants. The mixture of these primary and secondary pollutants forms photochemical smog.

Low visibility in cold weather is due to the unburnt carbon particles or hydrocarbons suspended in air.
This results in increase in impurity of the atmosphere and reduces the visibility.

Acid rain is caused by a chemical reaction that begins when compounds like sulphur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

Addition of phosphates and nitrates/fertilizers into water leads to nutrient enrichment which is also called as eutrophication. It is the enrichment of water bodies with excessive nutrients and fertilizers. This is a kind of water pollution, because excessive nutrients result in growth of plants and algae which consume oxygen present.

Biodegradable material is that which breaks down organically by bacteria and may be returned to the earth with none of the damage associated with the generation of typical waste materials.

Granite is the least susceptible to acid rain because its it is composed of feldspar and quartz, both of which resist attacks of acid.

Anaerobic biodegradation is the process of degrading compounds by microorganisms in the absence of oxygen. In this process, methane forms as the main product.

Soil acidity is often increased by the use of the large amounts of fertiliser needed for the potato crop in this region. To control soil acidity, farmers apply ground limestone to the soil, and then mix it in with tillage implements.

An ozone layer, present in the stratosphere, reflects the ultraviolet rays emitted by the sun and thus it prevents us from skin diseases and mutation.

Generally organic wastes are biodegradable, e.g. domestic sewage, discharge from food processing factories.

Smog is a type of air pollutant, is a combination of smoke and fog.
Classic smog results from large amounts of coal burning in an area and its caused by a mixture of smoke and sulphur dioxide.

Ringelmann's smoke charts show shades of grey by which the density of smoke can be compared. The darkness of a smoke depends upon the concentration and size of the particulate matter in the effluent.

Chlorofluorocarbon compounds are released from automobiles, refrigerators, etc.
These compounds cause an increase in atmospheric temperature causing global warming.

The most serious water pollutants are the disease causing agents, called pathogens.
Pathogens include bacteria and other organisms that enter into water from domestic sewage and animal excreta.

Wars among nations and industrialization release lots of harmful gases into the air which cause air pollution. Growth of algae in water causes the dissolved oxygen levels in water to deplete, resulting in death of aquatic animals due to water pollution. Afforestation does not cause pollution directly.

The ozone layer is present in the stratosphere above the Earth. The layer of ozone is responsible for the absorption of the harmful ultraviolet radiations from the solar radiations. Due to ozone depletion, these radiations enter the Earth's atmosphere and cause skin cancer. The radiations can also damage the eye and other exposed parts of the body. The radiations can also cause mutations like thymine dimer formation or breaking of the hydrogen bonds.