What type of flame results from mixing primary air with gas prior to ignition?

The correct answer is blue flame. A blue flame is produced when there is a proper mix of gas and primary air before ignition, which leads to complete combustion. This type of flame is characterized by a clean and efficient burn with minimal soot production, indicating that the gas is burning efficiently due to the correct air-to-fuel ratio.

In the context of combustion, when primary air is mixed with gas prior to ignition, it allows for a more thorough mixing of the fuel and oxidizer. The result is a hotter flame that is blue in color, which signifies that there is sufficient oxygen for combustion, promoting a complete and efficient burning process.

In contrast, a luminous flame typically appears yellow or orange and is associated with incomplete combustion, resulting in the production of soot or carbon particles that glow. This would not be the result of a proper mixture of primary air and gas prior to ignition.

A Bunsen flame usually refers to a specific type of flame produced in a Bunsen burner, which can appear in different forms (such as luminous or non-luminous) depending on the air supply adjustment. Without an appropriate mix of air and gas, it could produce either a yellow or blue flame.

Lastly, a yellow flame is indicative of incomplete combustion and