Free Environmental Chemistry MCQs with Answers

121. The biggest source of acid rain is the oxide of:

• A. N
• B. S
• C. O
• D. C

Explanation: Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the atmosphere and transported by wind and air currents.The biggest source of acid rain is the oxide of sulfur (S).Acid rain is formed when sulfur dioxide (SO2) and nitrogen oxides (NOx), primarily nitrogen (NO2), are released into the atmosphere as pollutants from various human activities, particularly the combustion of fossil fuels. These pollutants can undergo chemical reactions in the atmosphere and sulfuric acid (H2SO4) and nitric acid (HNO3), respectively. These acids can then combine with water vapor in the atmosphere and fall to the ground as acid rain.

122. The increase in the concentration of oxidizing agents in smog like H2O2, HNO3, PAN, and ozone in the air is called:

• A. Carbonated smog
• B. Nitrated smog
• C. Photochemical smog
• D. Sulphonated smog

Explanation: Photochemical smog is a mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds (VOCs) react to sunlight.

123. Which is the metal, whose elevated concentration is harmful to fish as it clogs the gills thus causing suffocation?

• A. Na
• B. Pb
• C. Zn
• D. Al

Explanation: Elevated levels of aluminum can affect some species' ability to regulate ions, like salts, and inhibit respiratory functions, like breathing. Aluminum can accumulate on the surface of a fish's gill, leading to respiratory dysfunction, and possibly death.

124. The unpolluted natural rainwater is slightly acidic due to the reaction of rain water with:

• A. Sulphur dioxide
• B. Oxides of nitrogen
• C. Carbon dioxide
• D. Hydrogen present in air

Explanation: Unpolluted rain has a slightly acidic pH of 5.6, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid. Also note that unpolluted air would not have A and B, hence C is the correct choice.

125. The suspected liver carcinogen which also has negative reproduction and developmental effects on humans is:

• A. Iodoform
• B. Bromoform
• C. Tropoform
• D. Chloroform

Explanation: Chloroform is a carcinogen, causing liver and kidney cancer after oral exposure, and has negative effect on reproduction and development of humans (and animals).

126. Peroxyacetyl nitrate is an irritant to human beings and it effects:

• A. Nose
• B. Stomach
• C. Ears
• D. Eyes

Explanation: Peroxyacetyl nitrates (PANs) have many adverse effects in the human body such as reduced respiratory function (including emphysema and impaired breathing) and eye irritation.

127. The pH of acid rain is:

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

Explanation: Acid rain has a pH of below 5.It is a fact and should be memorized.

128. _ is an eye irritant.

• A. Peroxyacetyl nitrate
• B. Peroxyacetyl nitrite
• C. Peroxy Methoxy aniline
• D. Peroxyacetyl aniline

Explanation: Peroxyacetyl nitrate (PAN) is a ubiquitous air pollutant formed from NO(2) reacting with acetoxy radicals generated from ambient aldehydes in the presence of sunlight and ozone. It contributes to eye irritation associated with photochemical smog and is present in most urban air.It is a fact.

129. Polystyrene is an additional polymer. Which one of the following structures representsthe monomer of polystyrene?

• A. CH2=CH2
• B. CH2=CH-CH3
• C. CH2=CH-Cl
• D. CH2=CH-C6H5

Explanation: Polystyrene (PS) is a synthetic aromatic hydrocarbon polymer made from the monomer known as styrene.

130. Which one of the following pollutants can cause death of a person by binding withhaemoglobin of red blood cells?

• A. Chlorofluorocarbons
• B. Oxides of Sulphur
• C. Carbon monoxide
• D. Oxides of nitrogen

Explanation: Carbon monoxide poisoning occurs when carbon monoxide builds up in your bloodstream. When too much carbon monoxide is in the air, your body replaces the oxygen in your red blood cells with carbon monoxide. This can lead to serious tissue damage, or even death.