Chemistry of Gases and Applications

Nitrogen is the primary gas used in fertilizer production. It's essential for making ammonia, urea, and ammonium nitrate - the three most widely used nitrogen fertilizers. Plants require nitrogen for protein synthesis and growth, making it crucial for agriculture.

Ethylene is a natural plant hormone that triggers and regulates the fruit ripening process. It's produced by fruits themselves and acts as a chemical signal that stimulates ripening, which is why placing unripe fruit near ripe fruit speeds up the process.

Primitive Earth had a reducing atmosphere composed of ammonia, methane, hydrogen, carbon dioxide, and nitrogen - but NO free oxygen. Oxygen only appeared later when photosynthetic cyanobacteria evolved and began producing it as a byproduct. This oxygen eventually accumulated to form our current oxygen-rich atmosphere.

Helium is the preferred gas for modern balloons and airships because it is non-flammable and inert. Hydrogen, while more buoyant, is extremely flammable and dangerous (as demonstrated by the Hindenburg disaster). Helium provides safe lift with only slightly less buoyancy.

Marsh gas is primarily methane (CH4), produced by anaerobic decomposition of organic matter in wetlands, swamps, and marshes. This is why methane is also called 'swamp gas.' Hydrogen, nitrogen, and ethane are not the primary components of marsh gas.

According to the most accepted theory, the Earth atmosphere, before any life had originated, consisted of H₂O, H₂, NH₂ and methane. 

Yes, it is the correct answer. In the secondary treatment of sewage, during digestion, bacteria produce a mixture of gases. But from the above given gases, nitrous oxide and oxygen are not produced.

Nitrous oxide (N2O) is called laughing gas because inhaling it produces euphoria and laughter-like effects. It was discovered by Humphry Davy and has been used as an anesthetic and recreational drug.

Carbon monoxide (CO) is a neutral oxide because it does not react with acids or bases. In contrast, GeO and SnO are amphoteric (react with both), while PbO is predominantly basic. CO's neutrality comes from carbon's intermediate position in the periodic table.

Gobar gas (biogas) primarily contains methane (50-70%), along with carbon dioxide (30-40%) and trace amounts of hydrogen sulfide. It is produced by anaerobic decomposition of organic matter (cow dung, etc.). Ethane is present in trace quantities only. 'Carbon' and 'Nitroflourine' are incorrect - carbon is not a gas at STP, and 'Nitroflourine' is not a recognized chemical term.

This option is correct.

Argon constitutes approximately 0.93% of Earth's atmosphere, making it the most abundant noble gas. Helium, xenon, and krypton are present in much smaller concentrations. Argon's abundance comes from the radioactive decay of potassium-40 in Earth's crust.

Krypton gas is used in high-speed photography because it produces a very bright, intense light with a short duration when electrically excited. This property makes it ideal for flash lamps used in photographic applications requiring freezing fast motion. Krypton-filled flash lamps provide consistent illumination for capturing rapid events.

Nitrous oxide (N2O) is commonly known as laughing gas due to its euphoric effects when inhaled. It was discovered in 1772 by Joseph Priestley and has been used as an anesthetic and analgesic in medical and dental procedures. The chemical formula N2O confirms that nitrous oxide is the correct answer.