Question

E. Tick the most correct and appropriate answer.

• A. carbon dioxide
• B. sulphur dioxide
• C. nitrogen
• D. noble gases

Answer 1

The correct option is C

nitrogen

Part 1: Composition of air

• Nitrogen$\left({\mathrm{N}}_2\right)$ and oxygen$\left({\mathrm{O}}_2\right)$ are the two main gases that make up most of the air.
• The air contains around $78\%$nitrogen, $20\%$ oxygen, and $1\%$water vapor which varies from place to place.
• Argon, another gas, makes up the most of the remaining $1\%(0.97\%)$ with carbon dioxide only around $0.03\%$

Part 2: A Gas that dilutes the activity of oxygen is:

• Nitrogen is a chemically inert gas
• As oxygen gas is a necessary reactant in the combustion process, nitrogen dilutes oxygen and prevents rapid or immediate burning at the Earth's surface.
• Living things require and utilize nitrogen to produce proteins, yet it is inaccessible to most living things in the form of nitrogen gas.
• All living creatures need oxygen to create molecules that are necessary for their survival. It's also required for aerobic respiration and combustion.

Hence, the correct answer is an option (C)