Chemistry of Gases and Applications

Marsh gas is the common name for methane (CH4), a simple hydrocarbon gas formed by anaerobic decomposition of organic matter in wetlands and marshes. Methane is the primary component of natural gas and is the simplest alkane with one carbon atom bonded to four hydrogen atoms. The other options either represent incorrect chemical formulas or combinations that don't correspond to marsh gas.

Carbon monoxide is not used as a refrigerant because it's highly toxic, flammable, and doesn't have suitable thermodynamic properties for cooling cycles. Ammonia, sulfur dioxide, and carbon dioxide have all been historically used as refrigerants in various applications. The question asks which is NOT used.

Methane (CH4) has more than doubled since the industrial revolution (approximately 700 ppb to 1800+ ppb). While CO2 has increased more in absolute terms, methane has approximately doubled in concentration, matching the question.

Nitrous oxide (N2O) is emitted from agricultural activities, particularly synthetic fertilizers and manure management. It is a potent greenhouse gas with 300x the global warming potential of CO2. Pesticide industries also contribute to N2O emissions.

Chlorine gas appears greenish-yellow, a distinctive property that makes it visually identifiable among common gases. Hydrogen, krypton, and neon are all colorless gases under standard conditions.

Thermobaric bombs (also called fuel-air explosives or vacuum bombs) use atmospheric oxygen as the oxidizer, unlike conventional explosives which carry their own oxygen source. Thermonuclear bombs use nuclear fusion, anti-tank mines are conventional explosives, and dirty bombs scatter radioactive material.

Pressurized tennis balls are filled with nitrogen gas (or sometimes air, which is mostly nitrogen) to maintain consistent bounce and feel. The internal pressure, typically around two atmospheres, helps the ball retain its performance characteristics during play. Oxygen would cause the rubber to degrade faster, while hydrogen is too reactive and carbon dioxide doesn't maintain pressure as effectively.

Ozone is an allotrope of oxygen consisting of three oxygen atoms (O3). Unlike the more common diatomic oxygen (O2) we breathe, ozone is a powerful oxidizing agent found primarily in the stratosphere where it forms the protective ozone layer.

Oxygen should NEVER be used in a fire extinguisher because it would intensify combustion rather than suppress it. Fire extinguishers use substances that smother flames (like CO2), cool them (like water), or interrupt chemical reactions (like certain dry chemicals). Adding oxygen is essentially adding fuel, making fires worse.

Water gas is a fuel gas consisting mainly of carbon monoxide (CO) and hydrogen (H2), produced by passing steam over red-hot coke. It was historically important for industrial heating and lighting. Option A incorrectly states carbon dioxide, Option B has a typo and incorrect chemistry, and Option D describes the reactants, not the product.

F1 tires are inflated with nitrogen-rich gas mixtures to maintain more consistent pressure and reduce pressure variations with temperature changes. While compressed air is mostly nitrogen anyway (about 78%), pure nitrogen eliminates moisture and oxygen that can cause pressure fluctuations.

Carbon dioxide is dissolved under pressure in champagne and soda, creating bubbles when released. Nitrogen is used in some beers but not common in champagne or soda. Hydrogen and oxygen are not the gases used for carbonation.

Chlorine is widely used for water purification and disinfection because it effectively kills bacteria, viruses, and other pathogens. It is added to water supplies in controlled amounts to make water safe for drinking. Oxygen and carbon dioxide are not used for purification, while ammonia is sometimes used in water treatment but not as a disinfectant.

Aqua fortis is Latin for 'strong water' and historically refers to nitric acid (HNO₃). Nitric acid is a strong corrosive acid, while nitrous oxide (N₂O) is a gas, and nitrogen (N₂) is an element.

Nitrous Oxide is commonly known as laughing gas because it causes euphoria and laughter when inhaled. It has been used as an anesthetic and pain reliever in medical and dental procedures for over a century.