Chemistry of Gases and Applications

This is the correct option. In the tertiary treatment, ozone gas can be used to kill the disease-causing organisms.

Dinitrogen tetroxide is the chemical compound N₂O₄. It is a powerful oxidizer, highly toxic and corrosive. N₂O₄ is hypergolic with various forms of hydrazine, i.e., they burn on contact without a separate ignition source, making them popular bipropellant rocket fuels.

The number of molecules in a given mass is inversely proportional to the molar mass. Hydrogen (H2) has the lowest molar mass (2 g/mol), so 1 gram of hydrogen contains the most molecules (0.5 moles). Carbon dioxide (44 g/mol), oxygen (32 g/mol), and ammonia (17 g/mol) all have higher molar masses, meaning the same mass contains fewer molecules. For example, 10g CO2 is only 0.23 moles.

Gobar gas (biogas from cow dung) is primarily methane (CH4), produced by anaerobic decomposition of organic matter. Methane makes up 50-75% of biogas, with the rest being CO2 and small amounts of other gases. Methane is the flammable component that allows biogas to be used as fuel.

Ammonia (NH3) is a widely used refrigerant, especially in industrial and large commercial refrigeration systems due to its excellent thermodynamic properties. While modern household refrigerators commonly use HFCs or hydrocarbon blends like isobutane, ammonia remains an important refrigerant in the industry.

The molecules of a gas have the highest kinetic energy.

Statement 1 is true: Launching heavy satellites weighing over 2 tons into geostationary orbit requires an upper stage powered by a cryogenic engine. Cryogenic engine is indispensable for such launch vehicles as this engine provides the required trust to the vehicle. Statement 2 is also correct: Cryogenic technology involves the use of liquid oxygen (as oxidizer) at minus 183 degrees Celsius and liquid hydrogen (as fuel) at minus 253 degrees Celsius.

The free oxygen produced by the blue-green algae converted the atmosphere from reducing into oxidising.

CNG stands for Compressed Natural Gas, which is primarily methane stored at high pressure for use as fuel. It's widely used in vehicles as a cleaner alternative to petrol or diesel.

Hydrogen Chloride gas is collected by upward displacement of air.

Hydrogen chloride gives white fumes of ammonium chloride with ammonia.

This is a test for hydrogen.

Hydrogen sulphide gas smells like rotten eggs.

Very little atmosphere, no organic material or organic supporting chemical (ie water), no life could occur.