Chemistry, Industry and the Environment

In the industrial biotechnology process of ethanol production from sugar molasses, fermentation is carried out using yeast. Which of the following best explains why the fermentation vessel must be kept anaerobic (oxygen-free) and maintained at a temperature below $40^\circ\text{C}$?

Match each atmospheric phenomenon or chemical process on the left with its precise molecular mechanism or cause on the right.

Under the influence of ultraviolet radiation in the stratosphere, chlorofluorocarbons (CFCs) undergo photolysis to yield reactive chlorine free radicals ($\text{Cl}^\bullet$). Which of the following chemical equations correctly represents the propagation step in which the chlorine radical directly reacts with ozone to cause its depletion?

Match each water treatment chemical or industrial effluent contaminant on the left with its correct chemical action or environmental impact on the right.

An agricultural soil contaminated by acid mine drainage displays an abnormally low pH of $4.0$, causing heavy metal ions such as $\text{Pb}^{2+}$ and $\text{Cd}^{2+}$ to remain highly soluble and toxic to crops. Which chemical substance is most appropriate to treat the soil to reduce acidity and precipitate these toxic metal ions?

Carbon(IV) oxide ($CO_2$) is the major chemical agent responsible for the depletion of the stratospheric ozone layer because it reacts directly with ozone ($O_3$) molecules upon absorbing ultraviolet radiation.

Match each environmental contaminant or waste management process in Column A with its corresponding chemical characteristic or primary effect in Column B.

In atmospheric chemistry, air pollutants are classified based on whether they are released directly from source emissions or formed via atmospheric reactions. Which of the following is a secondary pollutant produced during the formation of photochemical smog?

Match each soil pollutant or waste management technique in Column A with its corresponding chemical mechanism, bio-environmental effect, or operational principle in Column B.

Municipal solid waste containing large amounts of polyethene packaging materials is buried in a sanitary landfill. Over time, these materials persist in the soil without decomposing. Which chemical characteristic of synthetic addition polymers accounts for their resistance to biological waste degradation in soil?

In the stratosphere, ozone ($O_3$) serves as a protective layer by absorbing high-energy ultraviolet radiation, whereas in the troposphere, ozone functions as an air pollutant and a greenhouse gas.

A waste management facility categorizes organic polymers into synthetic addition polymers, such as polyethene, and natural or condensation polymers, such as starch and nylon-6,6. Upon microbial action, polyethene exhibits extreme resistance to decomposition. Which of the following statements correctly explains the chemical basis for the non-biodegradability of synthetic addition polymers compared to biodegradable natural polymers?

A river downstream from a processing factory exhibits a high Biochemical Oxygen Demand (BOD) reading following the discharge of organic effluent. Which process directly accounts for the depletion of dissolved oxygen in this aquatic environment?

Synthetic addition polymers, such as polyethene and polyvinyl chloride, are biodegradable because soil micro-organisms can readily break down their carbon-carbon backbone.

A waste management facility evaluates four industrial waste polymers: polyethene, starch, polyvinyl chloride (PVC), and nylon-6,6. Which of the following chemical statements correctly differentiates their biodegradation mechanisms and incineration hazards?

Two synthetic polymers, Polymer X (a polyamide formed by condensation polymerization) and Polymer Y (a polyalkene formed by addition polymerization), are buried in soil at a waste disposal site. Over time, Polymer X undergoes gradual microbial breakdown, whereas Polymer Y remains chemically intact for decades. What is the primary structural reason for this marked difference in biodegradability?

Organophosphate pesticides persist in agricultural soils for significantly longer periods than organochlorine insecticides because organophosphates resist chemical hydrolysis and microbial degradation.

Which of the following atmospheric pollutants acts primarily as a greenhouse gas by absorbing terrestrial infrared radiation, rather than destroying stratospheric ozone through catalytic radical chain reactions?

Continuous application of ammonium-based nitrogen fertilizers increases soil acidity, which mobilizes toxic heavy metal cations by displacing them from soil colloid exchange sites into the soil solution.

In a Nigerian chemical manufacturing plant producing soap from local palm oil, arrange the key industrial stages in the correct sequential order from raw material preparation to the final finished product.