What elements make up acetylene gas?

Acetylene gas is a hydrocarbon that consists of two elements: carbon and hydrogen. The chemical formula for acetylene is C₂H₂, indicating that it is made up of two carbon atoms and two hydrogen atoms bonded together. This unique combination of just these two elements is what gives acetylene its properties and makes it highly useful as a fuel gas, especially in welding and cutting applications due to its high flame temperature when burned with oxygen.

The other options, which include combinations of hydrogen with nitrogen, carbon with oxygen, and oxygen with nitrogen, do not pertain to the composition of acetylene, highlighting the specific need for carbon and hydrogen to form this particular gas. Understanding the correct elements that comprise acetylene is fundamental for anyone studying welding, as it is a central component in many welding processes.