When acetylene is combined with oxygen, where is the hottest part of the resulting flame?

• A. At the end of the inner cone
• B. At the base of the flame
• C. In the outer envelope
• D. In the middle of the flame

Answer: (A)

When acetylene is combined with oxygen, the hottest part of the resulting flame occurs at the end of the inner cone. In an oxy-acetylene flame, the flame has distinct regions: the inner cone, outer envelope, and base. The inner cone consists of unburned gases that have mixed and are beginning to combust, reaching maximum temperatures as they fully react with oxygen at the tip of this cone.

The chemical reaction between acetylene and oxygen releases energy in the form of heat, and this process peaks right at the end of the inner cone where combustion is most efficient. This area achieves temperatures of approximately 3,500 degrees Celsius (6,332 degrees Fahrenheit), making it ideal for various welding and cutting applications.

Understanding the structure of the flame is essential for effective and safe use in pipefitting and metalworking practices, as utilizing the flame’s hottest part maximizes efficiency and control in tasks that require intense heat.