Question

What type of Bunsen burner flame indicates complete combustion of methane?

Answer 1

Bunsen burner is an instrument that can be used in the laboratory to produce a single open gas flame used for heating, sterilizing, or combustion. Two different types of flames were produced in the Bunsen burner based upon the air hole and the substance that was heating on the Bunsen burner.

Complete answer:
Bunsen burner was named after a scientist Robert Bunsen. It is one of the main things that can be used for heating, sterilization and combustion. It is like a small gas that has one air hole, based on the air hole the flame will be different. Two different flames were observed in the Bunsen burner. One is yellow or orange flame and the other is blue flame.
Methane is an alkane that has the molecular formula of $C{H_4}$ , and when methane reacts with oxygen gas then combustion occurs and leads to the formation of carbon dioxide and water.
The blue flame will be observed when the air hole is opened, as oxygen is supplied in excess resulting in the complete combustion of methane gas.
Thus, a blue flame in the Bunsen burner indicates the complete combustion of methane.

Note:
Yellow flame is the safest flame that has nearly ${300^0}C$ temperature and occurs when the air hole is closed. The blue flame that can be produced when an air hole is opened and can occur at nearly ${500^0}C$ and it is invisible in a bright room. As the blue colour can be dominated by the bright colours present in the room.