Chemistry of Gases and Applications

Water vapor (H2O) constitutes about 60-90% of all volcanic gas emissions by volume. While CO2 and SO2 are significant, water vapor is by far the most abundant. Helium is present only in trace amounts. This makes option A correct.

Water is the most abundant compound on earth's surface, covering about 70 percent of the planet. In nature, water exists in liquid, solid and gaseous states.

Water vapor (H2O in gaseous form) is by far the most abundant gas emitted during volcanic eruptions, typically accounting for 60-90% of total volcanic gas emissions. This occurs because hot magma contains dissolved water from the original molten rock and from interactions with groundwater. Carbon dioxide (CO2) is the second most abundant (10-40%), while sulfur dioxide (SO2) and other gases are emitted in much smaller quantities. Helium is rare.

Helium is mixed with oxygen for respiration by divers in deep sea.

 Hydrogen and helium, the lightest two gases, weigh so little that helium balloons and hydrogen dirigibles are able to float in the atmosphere.

Hydrogen is used in the hydrogenation of vegetable oils to make vegetable ghee. 

Nitrogen is filled in bulbs. Argon is another noble gas and is used to keep light bulb filaments from burning away. Since argon is non-reactive, it is filled in a light bulb instead of regular air, which contains oxygen that can cause a burning reaction when exposed to the thin metal filaments found in light bulbs. Other noble gases include krypton, xenon and radon.

Helium is an element. Other options are compounds.

A mixture is a material, which consists of two or more pure substances (elements or compounds) which are not chemically combined but physically mixed in any proportion. A mixture shows the properties of all its constituents and it can be reported into its constituents by physical method. Air is a homogeneous mixture of many gases like nitrogen (78%), oxygen (21%), carbon dioxide, inert gases and water vapours. Air is a mixture because its properties are in between those of its constituents. The two major components of air are oxygen and nitrogen. In the presence of oxygen, any fuel burns brightly but in nitrogen it gets extinguished. In contrast, in air, the fuel burns slowly. The components of air can be separated by fractional distillation; moreover the composition of air is also variable. Thus, air is a mixture. An element is a pure substance that contains only one kind of atoms. A molecule is a group of two or more atoms, which are held together strongly by some kind of attractive force. For e.g. H₂, Cl₂, Br₂, etc. A compound is made up of two or more elements chemically combined in fixed proportion by mass. For e.g. H₂O, HCl, NH₃, etc.

Before life, Earth's atmosphere had ammonia, methane, and free hydrogen, but no free oxygen. Free oxygen only appeared after photosynthetic organisms evolved and started producing it as a byproduct.

Yeast is the organism, which is added to the dairy products to increase their volume. When the yeast cells multiply, they breathe and release carbon dioxide, which causes an increase in the volume of food products. 

The gas which leaked from the Union Carbide Plant in Bhopal in 1984 was methyl isocyanate. 

In telecommunications, a point-to-point connection refers to a communications connection between two nodes or endpoints. An example of this is a telephone call, in which one telephone is connected with one other, and what is said by one caller can only be heard by the other. Microwaves are widely used for point-to-point communications because their small wavelength allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna.

Life cannot currently originate from inorganic compounds because high oxygen levels oxidize and break down organic molecules before they can form complex life. Early Earth had little oxygen, allowing organic molecules to accumulate. The other options are incorrect - hydrogen is still available, raw materials exist, and temperature is suitable.

Correct answer. Among the given options, ammonia has the highest solubility in water.