Solubility of Gases in Water:

Solubility is the maximum amount of a substance that can dissolve in a given amount of solvent at a specific temperature and pressure. The solubility of a gas in water depends on various factors, such as temperature, pressure, and the chemical nature of the gas.

Factors Affecting Solubility of Gases in Water:

Temperature: The solubility of gases in water decreases with an increase in temperature.

Pressure: The solubility of gases in water increases with an increase in pressure.

Chemical Nature of the Gas: The solubility of gases in water depends on the chemical nature of the gas. Some gases are more soluble in water than others due to their chemical properties.

Least Soluble Gas in Water:

Out of the given options, nitrogen (N2) will be the least soluble gas in water. Nitrogen gas is relatively non-polar, which makes it less likely to dissolve in the polar solvent, such as water. The non-polar nature of nitrogen results in a weak interaction between nitrogen and water molecules, which decreases its solubility.

On the other hand, hydrogen chloride (HCl), sulphur dioxide (SO2), and ammonia (NH3) are more polar and have a stronger interaction with water molecules. Hence, they are more soluble in water than nitrogen gas.

Conclusion:

In conclusion, nitrogen gas will be the least soluble gas in water due to its non-polar nature. While hydrogen chloride, sulphur dioxide, and ammonia are more polar and more soluble in water.