Chemistry of Gases and Applications

Biogas usually contains about 55 - 65% methane.

LPG (Liquefied Petroleum Gas) primarily contains a mixture of propane and butane gases. These hydrocarbons can be easily liquefied under moderate pressure, making them ideal for storage and transport in cylinders for domestic and industrial use.

Carbon dioxide is commonly used in fire extinguishers because it's denser than air, so it settles over the fire and displaces oxygen. It also doesn't support combustion and helps cool the fire. Carbon monoxide is toxic and flammable, while sulphur dioxide is itself a toxic gas.

Chlorine is not naturally present in Earth's atmosphere as a stable gas component. The atmosphere primarily consists of nitrogen (78%), oxygen (21%), argon, carbon dioxide (0.04%), and trace gases. Chlorine exists as chlorofluorocarbons (CFCs) from human activity but not naturally. Option A has a typo ('Nitorgen' instead of 'Nitrogen').

Ammonia (NH3) is a compound composed of two different elements (nitrogen and hydrogen) chemically bonded in a fixed ratio. Air is a mixture of gases, Mercury is a pure element, and Ozone (O3) is a molecule of the same element. A compound must contain at least two different elements.

Nitrous oxide (N2O) is commonly called 'laughing gas' because it causes euphoria and laughter when inhaled. It's used as an anesthetic and analgesic in medical and dental procedures. The other options are incorrect: carbon dioxide (CO2) is a greenhouse gas, vanadium pentoxide is used in sulfuric acid production, and hydrogen sulfide (H2S) is a toxic gas with a rotten egg smell.

Ammonia is widely used in refrigeration plants and ice plants due to its excellent thermodynamic properties and low cost. It absorbs heat readily during evaporation, making it ideal for cooling applications. Noble gases like Xenon, Neon, and Argon are inert and not used in refrigeration.

It is known as Producer gas.

Sodium azide is the inorganic compound with the formula NaN3. This colourless azide salt is the gas-forming component in many car airbag systems. It is used for the preparation of other azide compounds. It is an ionic substance and is highly soluble in water. It is extremely toxic.

Ammonal is an explosive made up of ammonium nitrate, trinitrotoluene (TNT), and aluminium powder. Ammonium nitrate functions as an oxidizer and aluminium as a power enhancer. To some extent,  aluminium makes it more sensitive to detonation. The use of the relatively cheap ammonium nitrate and aluminium makes it a replacement for pure TNT.

HHTDD is a powerful but moisture sensitive explosive compound. It is essentially an open analogue of the cyclic nitroamine cage compounds such as CL-20. HHTDD readily decomposes in the presence of even trace amounts of water, making it unsuitable for any practical applications.

Hydrogen sulfide is a colourless, very poisonous, flammable gas with the characteristic foul odour of rotten eggs at concentrations up to 100 parts per million. It often results from the bacterial breakdown of organic matter in the absence of oxygen, such as in swamps and sewers.

Hydrogen peroxide (H₂O₂) is an oxidizer commonly used as a bleach. It is the simplest peroxide. Hydrogen peroxide is a clear liquid, slightly more viscous than water, that appears colourless in dilute solution. It is used as a disinfectant, antiseptic, oxidizer, and in rocketry as a propellant.