Which type of flame is characteristic of incomplete combustion?

• A. Yellow, smoky flame
• B. Green flame
• C. Colorless flame
• D. Blue, non-luminous flame

Answer: (A)

Verified step by step guidance

1. Understand the concept of combustion: Combustion is a chemical reaction between a fuel and oxygen that produces heat and light. It can be complete or incomplete depending on the availability of oxygen.
2. Recall that complete combustion occurs when there is sufficient oxygen, producing carbon dioxide and water, and typically results in a blue, non-luminous flame.
3. Recognize that incomplete combustion happens when oxygen supply is limited, leading to the formation of carbon monoxide, soot (carbon particles), and other byproducts.
4. Know that the presence of soot particles in incomplete combustion causes the flame to appear yellow and smoky because these particles get heated and emit yellow light.
5. Therefore, the characteristic flame of incomplete combustion is a yellow, smoky flame, distinguishing it from the blue, non-luminous flame of complete combustion.