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Our Earth is formed of multiple minute substances and particles that are involved in reactions that further form new ones. The field of chemistry that deals with the study of these reactions, transport, sources, effects, and fates of chemical species that are present in the air, water, and soil environments. It studies all the chemical and biochemical phenomena that occur in our nature. When there are unwanted chemical substances present in the environment, this leads to its contamination that causes pollution which further has harmful effects on the species living in nature.
MCQ on Environmental Chemistry
Ques 1. Which among the following is the most harmful air pollutant that is produced by automobiles?
- CO
- HNO3
- SO2
- NO
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Ans: a. CO
Explanation: The emissions which are emitted from the vehicles are a great contributor to the air pollution. These emissions are also responsible for the creation of smog which is harmful to the living beings. Carbon monoxide is a colorless and odorless air pollutant. Carbon monoxide when inhaled by the living beings, can lead to heart and health problems. On burning of the material like fuel, gas, coal, oil, etc, carbon monoxide is produced.
Ques 2. Which among the following is the main source of Soil and Water pollution?
- Mining
- Agro Industry
- Thermal Power Stations
- None of the above
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Ans: c. Thermal Power Stations
Explanation: A lot of gases are emitted from the thermal power plants which is also known as Thermal pollution. The environment is degraded by thermal pollution and the discharges of the waste or polluted water results in the water pollution. The emissions from the power plant have caused an increase in the soil suphate sulphur and also results in the decrease of Nitrogen which is present in the soil. Hence, leading to the soil pollution.
Ques 3. Water pollution is indicated by
- Amount of Nitrogen
- Amount of BOD
- Amount of Oxygen
- Amount of Hydrogen
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Ans: b. Amount of BOD
Explanation: BOD refers to the Biological Oxygen Demand. In the process of decomposition, the amount of oxygen required to remove the waste organic matter is referred as BOD. If there is not enough organic matter present in the water, then the BOD of the water is around 1-2 ppm. This water is considered very good and if the level increases to 3-5 ppm then the water is considered as moderately clean.
Ques 4. ________ is not a gaseous air pollutant,
- Fumes
- Ozone
- Carbon
- Hydrogen Sulphide
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Ans: a. Fumes
Explanation: The gaseous air pollutants that are responsible for air pollution are oxides of nitrogen, oxides of sulphur, hydrocarbon and carbon monoxide. These air pollutants are emitted on the burning of natural gas, fuel oil and gasoline. Fumes are categorized under particulate pollutants. Dust, smog, smoke, mist, etc. are a few examples of particulate pollutants.
Ques 5. Which of the following gas is a major cause of ozone depletion?
- Release of CO
- Release of CFC
- Release of CH4
- Release of CO2
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Ans: b. Release of CFC
Explanation: When the CFC gases rise into the stratosphere, which is one of the four spheres of the earth, they can deplete the ozone layer. UV radiations are hazardous to human beings and living organisms and ozone layer protects us from these harmful radiations. The exposure of human beings to these radiations can result in skin cancer. CFC when rise to stratosphere gets broken down by strong UV radiations and thus results in the release of chlorine atom which then will reach with the ozone molecules. In this way, the ozone is utilized resulting in lack of the ozone molecules.
Ques 6. Which of the following options is a viable pollutant?
- Fly Ash
- Oil Smoke
- Moulds
- Dry leaves
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Ans: c. Moulds
Explanation: Viable pollutants are the organic particulates that are dispersed in the air. Bacteria, Fungi, Algae and moulds are viable particulates that are dispersed in the atmosphere. These particulates are minute living organisms.
Ques 7. The main constituents of the acid rain are:
- Nitrogen and hydrogen
- Sulphur and oxygen
- Carbon and Nitrogen
- Sulphur and Nitrogen
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Ans: d. Sulphur and Nitrogen
Explanation: Acid rain includes the acidic components such as nitric or sulfuric acids that falls on the ground in the dry or wet forms. Acid rain is harmful in many forms and it affects the aquatic life. It also is responsible for the damage to buildings and historical monuments. As the acid rain flows to the soil, it also results in the damaging of the soil clay particles.
Ques 8. Which is the coldest region of the atmosphere?
- Thermosphere
- Troposphere
- Mesosphere
- Stratosphere
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Ans: c. Mesosphere
Explanation: The top layer of the earth’s atmosphere is Mesosphere as the temperature is as low as -173°C. The air in this layer is so thin than in stratosphere. The air molecules that absorbs the incoming electromagnetic radiation that is emitted from the sun. The top of Mesosphere, which is known as Mesopause, is the coldest part of the earth’s atmosphere.
Ques 9. For the life on earth, which of the following is the most harmful?
- Deforestation
- Increasing Desert
- Soil Erosion
- Nuclear Fallout
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Ans. d. Nuclear Fallout
Explanation: During a nuclear blast, the radio active residual which is propelled in the environment is known as Nuclear Fallout. The damage caused due to this Nuclear Fallout will appear over many years. The fallout exposure can lead to radiation poisoning that results in damaging of the cells of the body and are fatal.
Ques 10. The compound which is essential for photosynthesis process has __ element.
- Mg
- Fe
- Ba
- Ca
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Ans: a. Mg
Explanation: The central atom of the chlorophyll is formed with the help of Magnesium. Plants require the mineral nutrients like Magnesium and potassium. All the plants/crops require Magnesium to capture the sun’s energy for their growth and helps in photosynthesis. Each atom of chlorophyll consists of 6.7% magnesium. Due to the deficiency of Magnesium, the plants growth is affected and there’s a shortage of chlorophyll.
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