Question

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

Answer 1

Do you mean `"CH"_4` gas? I don't know what you mean by `"sp"^3` being red-orange. The following information is about the appearance of a Bunsen burner flame with incomplete and complete combustion of methane gas.

Complete and incomplete combustion can be seen with a Bunsen burner flame. When the air-hole is open, complete combustion occurs because enough air can mix with the gas so there is enough oxygen for the gas to react completely.

The flame when the air-hole is open is blue, luminous, and clean.

When the air-hole is closed, however, there is less oxygen available. This results in incomplete combustion of the gas.

The color of the flame changes to yellow and the flame is wavy. The yellow color is produced from particles of carbon (soot) in the flame which results from incomplete combustion of the methane gas.
http://www.bsquaredfutures.com/pluginfile.php/273/mod_imscp/content/1/lo_4-1-scorm/lo_4-1-scorm/index.html

![https://useruploads.socratic.org/1bjSQptScSUGeaygYkwO_methanecombustion.png)