Free Environmental Chemistry MCQs with Answers

181. Fossil fuels are produced due to _.

• A. Fast decomposition of organic matter
• B. Decomposition of plants
• C. Decomposition of animals
• D. Biochemical decomposition of dead organic matter

Explanation: Fossil energy sources, including oil, coal and natural gas, are non-renewable resources that formed when prehistoric plants and animals died and were gradually buried by layers of rock.

182. The disadvantage of use of chlorinated water is:

• A. Formation of NH4Cl , NHCl2 , NCl3 which are eye irritants
• B. Increased risk of bladder and rectal cancer by drinking water
• C. Offensive odour and taste due to chlorinated phenols.
• D. All of the above

Explanation: Disadvantages as advised by CDC guidelines for chlorinated water include following: The drawbacks of chlorination are: Relatively low protection against protozoa Lower disinfection effectiveness in turbid waters Potential taste and odor objections Must ensure quality control of solution Potential long-term effects of chlorination by-products

183. The yellowish colour of photochemical smog is due to the presence of:

• A. Nitrogen dioxide
• B. Dinitrogen trioxide
• C. Nitrous oxide
• D. Nitric oxide

Explanation: Explanation:The yellowish color of photochemical smog is primarily due to the presence of nitrogen dioxide (NO2), which is a brownish-yellow gas. Dinitrogen trioxide (N2O3) and nitric oxide (NO) are also nitrogen oxides, but they donot contribute significantly to the color of photochemical smog. Nitrous oxide (N2O) is a different compound that is not typically present in photochemical smog.

184. The incarnation process can reduce the volume of the water by:

• A. One half
• B. Not affected
• C. One third
• D. Two third

Explanation: Explanation:The incarnation process can reduce the volume of the water by two third. These options are also incorrect. The incarnation process can reduce the volume of the water by two third, not by one half or one third respectively. This option is also incorrect. the incarnation process can affect the volume of the water by two third.

185. The acid rain water has pH:

• A. Below 5
• B. 7
• C. Between 5 and 7
• D. Between 7 and 14

Explanation: It results from high levels of atmospheric nitric and sulfuric acids that get washed down to earth. Oxidation of sulfur and nitrogen in coal or other fossil fuels leads to the generation of acidic pollutants in the atmosphere.

186. Ozone is a layer of atmosphere extending from _ km above Earth and absorbs ultraviolet radiation.

• A. 10-50
• B. 50-60
• C. 5-30
• D. 10-80

Explanation: 10-50 km: This option is the correct answer. The ozone layer is a layer of the Earth's atmosphere that extends approximately 10-50 km above the Earth's surface. This layer plays a crucial role in absorbing the majority of the Sun's ultraviolet (UV) radiation, protecting life on Earth from harmful UV rays.

187. Light rays from the sun are absorbed by CO2 and re-radiate as _ radiations.

• A. Ultraviolet
• B. Indigo
• C. Infra-Red
• D. Green

Explanation: Infra-Red: This option is the correct answer. Light rays from the sun, including visible and ultraviolet light, can be absorbed by CO2 in the Earth's atmosphere. The absorbed energy is then re-radiated by CO2 as infrared (IR) radiation. This process contributes to the greenhouse effect and the warming of the Earth's atmosphere.

188. The gases which are produced by burning of fossils fuels and are responsible for acid rain are:

• A. CFCs
• B. CO2 and CO
• C. HCL and Oxides of Nitrogen
• D. SO2 and Oxides of Nitrogen

Explanation: SO2 and Oxides of Nitrogen: This option is the correct answer. Sulfur dioxide (SO2) and nitrogen oxides (NOx) are the main gases produced by the burning of fossil fuels that contribute to acid rain. These gases are released into the atmosphere as byproducts of burning coal, oil, and gas. When they react with water vapor and other atmospheric components, they form sulfuric acid (H2SO4) and nitric acid (HNO3), respectively, which contribute to the acidity of rainwater.

189. _is the major source of acid deposition in the atmosphere.

• A. SiO2
• B. CO2
• C. SO3
• D. Al2O3

Explanation: SO3 reacts with rain water to form H2SO4 (sulfuric acid) which is a major source of acid rain.

190. The energy from ultraviolet light is sufficient to break the _ bonds in CCl2F2.

• A. Cl-Cl
• B. Cl-F
• C. C-Cl
• D. C-F

Explanation: The Cl-F bond is less stronger than the C-Halide bond as it can be broken down by sunlight or UV radiation.