If the Bunsen burner gave a luminous flame and some soot was deposited on the tube, what effect would this situation have on the calculated % of oxygen ?​

Explanation:

If bunsen burner gave a luminous flame then there will deposition of soot at the bottom of the test tube which is actually pure carbon.

This deposition of soot actually depicts that there is incomplete combustion reaction that has taken place.

Also, the deposition of soot will provide a limited supply of oxygen to the reaction that has been calculated.

Therefore, in order to avoid any formation of soot it is advisable to adjust the burner flame till it produces a blue flame.